BIO-ECOLOGY AND MANAGEMENT OF MANGO MEALYBUG, DROSICHA MANGIFERAE GREEN IN MANGO ORCHARDS OF PUNJAB, PAKISTAN
By
HAIDER KARAR Reg. No. 84-ag-853 M.Sc .(Hons.) Agriculture
A thesis submitted in partial fulfillment of the requirements for the degree of
DOCTOR OF PHILOSOPHY IN AGRICULTURAL ENTOMOLOGY
FACULTY OF AGRICULTURE UNIVERSITY OF AGRICULTURE, FAISALABAD (PAKISTAN) 2010
DEDICATED To My Mother MY HEAVEN LIES BENEATH HER FEET
&
My Wife Raeesa Haider FOR HER SERVICES TO MY MOTHER & LOOKING AFTER THE CHILDREN
OH! MY ALMIGHTY ALLAH,
MAKE ME
AN INSTRUMENT OF YOUR PEACE WHERE , THERE IS HATRED , LET ME SOW LOVE ,
WHERE THERE IS INJURY , PARDON WHERE THERE IS DOUBT , FAITH WHERE THERE IS DESPAIR , HOPE
WHERE THERE IS DARKNESS , LIGHT AND WHERE THERE IS SADNESS , ENJOY .
CONTENTS
CHAPTER CONTENTS PAGE
LIST OF TABLES ------i LIST OF FIGURES ------v LIST OF APPENDICES ------vi LIST OF ABBREVIATIONS ------vii ACKNOWLEDGEMENT ------viii ABSTRACT ------ix
I INTRODUCTION
1.1 Agriculture in Pakistan ______1 1.2 The importance of fruits to Pakistan ______1 1.3 Importance of mango ______2 1.4 Insect pest of mango ______2
II REVIEW OF LITERATURE
2.1 Survey ------4 2.2 Population Dynamics ------4 2.3 Cultivar Resistance ------5 2.4 Effect of host plant ------6 2.5 Biology ------6 2.6 Selectivity Studies ------7 2.6.1 Cultural control ------7 2.6.2 Mechanical control ------8 2.6.3 Chemical control ------9 2.7 Sustainable management approach for the control of mango mealybug ------10
III PROBLEM ORIENTATION STUDIES
Abstract ------12 3.1 Introduction ------13 3.2 Materials and Methods ------14 3.2.1 Study Sites and its Climate ------14 3.2.2 Preliminary Survey ------14 3.2.3 Comprehensive Survey ------14 Contents
3.3 Results and Discussion ------16 3.3.1 Preliminary Survey ------16 3.3.1.1 Awareness among Farmers about Insect Pests ------16 3.3.1.2 Relationship between Pest and Yield Losses ------17 3.3.1.3 Dominance Factors of Mango Mealybug ------18 3.3.2 Comprehensive Survey ------19 3.3.2.1 Respondent’s Knowledge about Resistant and Susceptible Cultivars of Mango ------19 3.3.2.2 Awareness Regarding Methods of Spreading of Mealybug ------20 3.3.2.3 Awareness among Respondents Regarding Hibernation Places of Mango Mealybug ------21 3.3.2.4 Practices Adopted by the Farmers for the Control of Mango Mealybug ------22 3.3.2.4.1 Cultural Practices ------22 3.3.2.4.2 Mechanical Practices ------23 3.3.2.4.3 Response of Chemical Insecticide ------24 3.3.2.5 Practices Adopted by the Farmer to Control the Fertilized Female of Mango Mealybug Coming down the Tree ------25 3.3.2.6 Yield Losses by Mango Mealybug ------26 3.3.2.7 Major Problems Faced by the Farmers ------27 3.4 Discussion ------28
IV POPULATION DYNAMICS, CULTIVAR RESISTANCE AND BIOLOGY
Abstract ------31 4.1 Introduction ------32 4.2 Materials and Methods ------34 4.2.1 Population dynamics of Mealybug on Chaunsa Cultivar of Mango ------34 4.2.2 Population of mango Mealybug on different Cultivars of Mango ------34 4.2.3 Methodology to Study the Biology of Mango Mealybug under Field Conditions ------35 4.2.3.1 Collection of eggs ------36 4.2.3.2 Hatching of Eggs ------36 4.3 Results and Discussion ------38 4.3.1 Population of mango mealybug versus plant sides ------38 4.3.1.1 Population of Mango Mealybug on Leaves on Various Plant Sides ------38 4.3.1.2 Mango Mealybug on Inflorescence ------40 4.3.1.3 Mango Mealybug on Branches ------41 4.3.1.4 Population of Mango Mealybug on Trunk and Weeds------42 Contents
4.3.1.5 Predation, Parasitization and Fungal Attacked Population of Mango Mealybug ------42 4.3.2 Graphical interaction between weather factors and population of mango mealybug during 2005- 2006 and 2006-2007 ------43 4.3.2.1 Population of Mango Mealybug versus Weather Factors during 2005-2006 ------43 4.3.2.2 Population of Mango Mealybug versus Weather Factors during 2006-2007 ------44 4.3.2.3 Population of Mango Mealybug versus Weather Factors on an Average Basis of Both Years Data ------45 4.3.3 Role of weather in population fluctuation of mango mealybug ------47 4.3.3.1 Simple Correlation Between Weather Factors and Population of Mango Mealybug ------47 4.3.3.2 Multiple Linear Regression Models ------47 4.3.4 Active period of nymphs moving up the trees at various day times ------49 4.3.5 Population of mango mealybug on different cultivars of mango ------50 4.3.5.1 Population of Mango Mealybug During 2005- 2006 ------50 4.3.5.1.1 Cultivars Resistance ------51 4.3.5.1.2 Plant Direction ------52 4.3.5.1.3 Period of Abundance of Mango Mealybug ------52 4.3.5.2 Population of Mango Mealybug During 2006- 2007 ------53 4.3.5.2.1 Cultivars Resistance ------54 4.3.5.2.2 Plant Direction ------54 4.3.5.2.3 Period of Abundance ------54 4.3.5.3 Population of Mango Mealybug on Cumulative Basis of Both Years Studies ------57 4.3.6 Antibiosis Resistance Against Mango Mealybug in Different Cultivars of Mango ------59 4.3.6.1 Number of Eggs Laid Per Female ------59 4.3.6.2 Weight of Female ------60 4.3.6.3 Length of Female ------60 4.3.6.4 Width of Female ------62 4.3.6.5 Length of Ovisac ------62 4.3.6.6 Width of Ovisac ------62 4.3.7 Biology of mango mealybug on susceptible cultivar Chaunsa ------63 4.3.7.1 First Stadium ------63 4.3.7.2 Second Stadium ------63 Contents
4.3.7.3 Third Stadium ------64 4.3.7.4 Females ------64 4.3.7.5 Males ------65 4.3.8 Study on the behaviour of the pest ------65 4.3.8.1 Speed of Nymphs ------65 4.3.8.2 Removal of Whitish Cocoon ------65 4.3.8.3 Egg Laying Behaviour ------66 4.3.8.4 Nymphs Live Without Food ------66 4.3.8.5 Copulation Time ------66 4.4 Discussion ------68 Biology and Behaviour of Mango Mealybug on Chaunsa Cultivar ------70 Period of abundance ------70
V CULTIVAR RESISTANCE BASED ON BIOCHEMICAL ANALYSIS IN LEAVES AND INFLORESCENCE
Abstract ------71 5.1 Introduction ------72 5.2 Materials and Methods ------73 5.2.1 Moisture Content ------73 5.2.2 Total Minerals ------73 5.2.3 Nitrogen ------74 5.2.4 Crude Protein ------74 5.2.5 Fat Contents ------74 5.2.6 Crude Fibre ------74 5.2.7 Soluble Carbohydrates ------75 5.2.8 Sample Digestion for Macro Nutrients ------75 5.2.8.1 Phosphorus ------75 5.2.8.2 Potassium and Sodium ------75 5.2.9 Statistical Correlations ------75 5.3 Results and Discussion ------77 5.3.1 Chemical Factors in Leaves of different Cultivars of Mango ------77 5.3.1.1 Nitrogen ------77 5.3.1.2 Potassium ------78 5.3.1.3 Crude Fiber ------78 5.3.1.4 Fat Contents ------78 5.3.1.5 Sodium Contents ------80 5.3.1.6 Ash Contents ------80 5.3.1.7 Carbohydrate ------80 5.3.1.8 Phosphorus ------81 5.3.1.9 Moisture ------81 5.3.1.10 Crude Protein ------81 5.3.2 Chemical Factors in Inflorescence in Different Cultivars of Mango ------82 Contents
5.3.2.1 Nitrogen ------82 5.3.2.2 Potassium ------82 5.3.2.3 Crude Fibre ------83 5.3.2.4 Fat Contents ------83 5.3.2.5 Sodium ------83 5.3.2.6 Ash Contents ------84 5.3.2.7 Carbohydrate ------84 5.3.2.8 Phosphorus ------86 5.3.2.9 Crude Protein ------86 5.3.3 Impact of Various Chemical Factors on the Population of Mango Mealybug ------86 5.3.3.1 Simple Correlation ------86 5.3.3.2 Multiple Linear Regression Models ------87 5.3.3.2.1 Impact of Chemical Factors in Population Fluctuation of Mango Mealybug on Leaves ------87 5.3.3.2.2 Impact of Chemical Factors in Population Fluctuation of Mango Mealybug on Inflorescence ------89 5.4 Discussion ------91
VI LOSSES IN MANGO YIELD CAUSED BY MANGO MEALYBUG
Abstract ------93 6.1 Introduction ------94 6.2 Materials and Methods ------95 6.3 Results and Discussion ------95 6.3.1 Initial Mango Fruits in Treated and Untreated Trees ------96 6.3.2 Mango Fruits Obtained at Maturity in Treated and Untreated Trees ------97 6.3.3 Population of Mango Mealybug recorded per Inflorescence in Treated and Untreated Trees ------99 6.4 Discussion ------101
VII SUSTAINABLE MANAGEMENT OF MANGO MEALYBUG ON MANGO TREES
ABSTRACT ------102 7.1 Introduction ------103 7.2 Materials and Methods ------106 7.2.1 Selectivity Studies ------106 7.2.1.1 Cultural Control ------106 7.2.1.1.1 Hoeing/Ploughing ------106 Contents
7.2.1.1.2 Earthing/Mounding the tree trunk with fine soil ------106 7.2.1.1.3 Earthing/Mounding the tree trunk with clods, fallen leaves and debris ------107 7.2.1.1.4 Mounds of clods, fallen leaves and debris on plastic sheet ------107 7.2.1.1.5 Removal of soil from the orchard ------107 7.2.1.1.6 Intercropping ------107 7.2.1.1.7 Unploughed orchard------108 7.2.1.2 Mechanical control ------108 7.2.1.3 Chemical control ------115 7.2.1.3.1 Control of mango mealybug under laboratory ------115 7.2.1.3.2 Control of mango mealybug under field conditions ------116 7.2.2 Sustainable management of mango mealybug ------117 7.2.2.1 Cultural practices ------117 7.2.2.2 Mechanical practices ------118 7.2.2.3 Chemical practices ------118 7.2.2.4 Mechanical x chemical practice ------118 7.2.2.5 Cultural x mechanical practice ------118 7.2.2.6 Cultural x chemical practice ------119 7.2.2.7 Cultural x mechanical x chemical practices ------119 7.2.2.8 Control ------119 7.2.3 Management of Males of Mango Mealybug ------119 7.2.3.1 Management through Light traps ------119 7.2.3.2 Management through cultural practices ------119 7.3 Results and Discussion ------120 7.3.1 Cultural Methods for the Control of Mango Mealybug ------120 7.3.2 Mechanical methods of control ------124 7.3.2.1 Effect of Bands on the Nymphs of Mango Mealybug During 2006 ------124 7.3.2.2 Effect of Bands on the Nymphs of Mango Mealybug during 2007 ------126 7.3.2.3 Average Effect of Bands on the Nymphs of Mango Mealybug During 2006 and 2007 ------127 7.3.3 Chemical Control of Mango Mealybug ------129 7.3.3.1 In Vivo Mortality of First Instar Mango Mealybug One Day After Treatment ------129 7.3.3.2 Mortality of Mango Mealybug Two Days After Treatment ------129 7.3.3.3 Mortality of Mango Mealybug Three Days After Treatment ------130 7.3.3.4 Mortality of Mango Mealybug 4 Days After Treatments ------130 Contents
7.3.3.5 Mortality of Mango Mealybug 5 Days After Treatment ------132 7.3.3.6 Mortality of Mango Mealybug 6 Days After Treatment ------132 7.3.3.7 Mortality of First Instar Mango Mealybug under Field Conditions ------132 7.3.3.7.1 Mortality of First Instar Mango Mealybug 24 Hours After Spray ------132 7.3.3.7.2 Mortality of First Instar Mango Mealybug 72 Hours After Spray ------133 7.3.3.7.3 Mortality of First Instar Mango Mealybug 168 Hours After Spray ------133 7.3.3.8 Mortality of Second and Third Instars Mango Mealybug ------134 7.3.3.8.1 Mortality of Second and Third Instars Mango Mealybug 24 Hours After Spray ------134 7.3.3.8.2 Mortality of Second and Third Instars Mango Mealybug 72 Hours After Spray ------136 7.3.3.8.3 Mortality of Second and Third Instars Mango Mealybug 168 Hours After Spray ------136 7.3.3.9 Mortality of Adult Female of Mango Mealybug at Various Post Treatments Intervals ------136 7.3.3.9.1 Mortality of Adult Female of Mango Mealybug 24 Hours After Spray ------137 7.3.3.9.2 Mortality of Adult Female of Mango Mealybug 72 Hours After Spray ------137 7.3.3.9.3 Mortality of Adult Female of Mango Mealybug 168 Hours After Spray ------137 7.3.3.10 Sustainable management approach for the control mango mealybug ------138 7.3.3.11 Management of Mango Mealybug Males ------140 7.4 Discussion ------144 7.4.1 Control of Mango Mealybug through Cultural Practices ------144 7.4.2 Control of Mango Mealybug Through Mechanical Methods ------145 7.4.3 Control of Mango Mealybug Through Insecticides ------145 7.4.4 Sustainable Management Approach for the Control of Mango Mealybug ------146 7.4.5 Management of Males of Mango Mealybug ------147
VIII SUMMARY
Contents
Population Dynamics ______149 Cultivar Resistance ______150 Biology and Behaviour of the pest ______151 Effect of Environment on the population of Mango mealybug ______151 Period of abundance ______152 Biochemical analysis of leaves and inflorescence ______152 Losses caused by Mango mealybug ______152 Sustainable Management of Mango mealybug ______153 8.1 Recommendations ------155 8.2 Condition of the Pest and Recommended Practices ------156 8.3 Precautionary Measures ------157 LITERATURE CITED ------158 APPENDICES ------179
LIST OF TABLES
Chapter III
TABLE NO. TITLE PAGE NO.
1. AWARENESS OF THE RESPONDENTS ABOUT DIFFERENT INSECT PESTS OF MANGO ------17 2. PESTWISE EXTENT OF DAMAGE TO MANGO FRUIT AS TOLD BY THE RESPONDENTS ------18 3. VIEWS OF THE RESPONDENTS REGARDING MANGO MEALYBUG AS A VERY SERIOUS PEST ------18 4. AWARENESS AMONGST THE RESPONDENTS REGARDING SUSCEPTIBILITY AND RESISTANT MANGO CULTIVARS AGAINST MANGO MEALYBUG ------20 5. AWARENESS AMONGST THE RESPONDENTS REGARDING METHOD OF SPREADING OF MANGO MEALYBUG ------21 6. AWARENESS AMONGST THE RESPONDENTS REGARDING PLACES OF HIBERNATION OF MANGO MEALYBUG ------22 7. AWARENESS AMONGST THE RESPONDENTS REGARDING CULTURAL PRACTICES OF MANGO MEALYBUG ------23 8. AWARENESS AMONGST THE RESPONDENTS REGARDING MECHANICAL PRACTICES OF MANGO MEALYBUG ------24 9. AWARENESS AMONGST THE RESPONDENTS REGARDING CHEMICAL CONTROL OF MANGO MEALYBUG ------25 10. AWARENESS AMONGST THE RESPONDENTS REGARDING FERTILIZED FEMALE OF MANGO MEALYBUG COMMING DOWN THE TREES ------26 11. AWARENESS AMONGST THE RESPONDENTS REGARDING LOSSES AND YIELD OF MANGO MEALYBUG ------26 12. AWARENESS AMONGST THE RESPONDENTS REGARDING MAJOR PROBLEMS FACED BY MANGO GROWERS ------27
Chapter IV
1. POPULATION OF MANGO MEALYBUG ON CULTIVAR CHAUNSA ON VARIOUS PLANT PARTS DURING 2005-06 AND 2006-07------39
2. EFFECT OF WEATHER FACTORS ON THE POPULATION FLUCTUATION OF MANGO MEALYBUG DURING THE STUDY YEARS 2005-2006 AND 2006-2007. ------47
i List of Tables
3. MULTIPLE LINEAR REGRESSION MODELS BETWEEN POPULATION OF MANGO MEALYBUG AND WEATHER FACTORS ------48 4. ACTIVATION TIME OF MANGO MEALYBUG NYMPHS DURING THE DAY------50 5a. MEANS COMPARISON OF THE DATA REGARDING POPULATION OF MANGO MEALYBUG ON DIFFERENT CULTIVARS OF MANGO AT VARIOUS PLANT SIDES DURING 2005-06. ------51 5b. MEAN COMPARISON OF THE DATA REGARDING POPULATION OF MANGO MEALYBUG ON DIFFERENT DATES AT VARIOUS PLANT SIDES DURING 2005-2006. ------53 6a. MEANS COMPARISON OF THE DATA REGARDING POPULATION OF MANGO MEALYBUG ON DIFFERENT CULTIVARS OF MANGO AT VARIOUS PLANT SIDES DURING 2006-2007. ------55 6b. MEAN COMPARISON OF THE DATA REGARDING POPULATION OF MANGO MEALYBUG ON DIFFERENT DATES OF OBSERVATION AT VARIOUS PLANT SIDES DURING 2006-2007 ------56 7a. MEAN COMPARISON OF THE DATA REGARDING POPULATION OF MANGO MEALYBUG ON DIFFERENT CULTIVARS OF MANGO AT VARIOUS PLANT SIDES (AVERAGE OF BOTH YEARS) ------58 7b. MEAN COMPARISON OF THE DATA REGARDING POPULATION OF MANGO MEALYBUG ON DIFFERENT DATES OF OBSERVATION AT VARIOUS PLANT SIDES (AVERAGE OF BOTH YEARS) ------59 8. MEANS COMPARISON OF THE DATA REGARDING BIOLOGICAL PARAMETERS OF MANGO MEALYBUG FEEDING ON DIFFERENT CULTIVARS OF MANGO UNDER FIELD CONDITION ------61 9. LIFECYCLE OF MANGO MEALYBUG ON CHAUNSA MANGO ON AN AVERAGE ------64
Chapter V
1. MEAN COMPARISON OF THE DATA REGARDING CHEMICAL CONSTITUENTS (%) OF LEAVES IN DIFFERENT CULTIVARS OF MANGO ------78 2. MEAN COMPARISON OF THE DATA REGARDING CHEMICAL CONSTITUENTS (%) OF INFLORESCENCE IN DIFFERENT CULTIVARS OF MANGO ------85 3. SIMPLE CORRELATION BETWEEN POPULATION OF MEALYBUG ON MANGO LEAVES AND INFLORESCENCE ALONG WITH BIOCHEMICAL FACTORS ------87 4. MULTIPLE LINEAR REGRESSION MODELS BETWEEN POPULATION OF MEALYBUG ON MANGO LEAVES AND BIOCHEMICAL FACTORS ALONG WITH COEFFICIENT OF DETERMINATION VALUES ---- 89
ii List of Tables
5. MULTIPLE LINEAR REGRESSION MODELS BETWEEN POPULATION OF MEALYBUG ON MANGO INFLORESCENCE AND BIOCHEMICAL FACTORS ALONG WITH COEFFICIENT OF DETERMINATION VALUES ------90
Chapter VI
1. MEANS COMPARISON OF THE DATA REGARDING NUMBER OF MANGO FRUITS PER INFLORESCENCE IN TREATED AND UNTREATED TREES AT INITIAL STAGE ON DIFFERENT CULTIVARS OF MANGO ------97 2. MEANS COMPARISON OF THE DATA REGARDING NUMBER OF MANGO FRUITS OBTAINED IN UNTREATED AND TREATED TREES AT MATURITY ON DIFFERENT CULTIVARS OF MANGO ------98 3. MEAN COMPARISON OF THE DATA REGARDING POPULATION OF MANGO MEALYBUG RECORDED PER INFLORESCENCE IN DIFFERENT CULTIVARS OF MANGO ------99
Chapter VII
1. MEAN COMPARISON OF THE DATA REGARDING REDUCTION PERCENTAGE OF NYMPHS OF MANGO MEALYBUG IN DIFFERENT TREATMENTS AND MONTHS OF THE YEAR DURING 2006 AND 2007 ------121 2. MEAN COMPARISON OF THE DATA REGARDING REDUCTION IN PERCENTAGE OF NYMPHS OF MANGO MEALYBUG IN DIFFERENT TREATMENTS DURING 2006 AND 2007 ------122 3 MEAN COMPARISON OF THE DATA REGARDING PERCENT REDUCTION OF FIRST INSTARS NYMPHS OF MANGO MEALYBUG IN DIFFERENT TREATMENTS DURING 2006 AND 2007 ------123 4. MEAN COMPARISON OF THE DATA REGARDING PERCENT POPULATION CROSSED THE TESTING BAND DURING 2006 ----- 125 5. MEAN COMPARISON OF THE DATA REGARDING PERCENT POPULATION CROSSED THE TESTING BAND DURING 2007 ----- 127 6. MEAN COMPARISON OF THE DATA REGARDING PERCENT POPULATION CROSSED THE TESTING BAND DURING 2006 AND 2007 ------128 7. MEAN COMPARISON OF FIRST INSTAR MANGO MEALYBUG PERCENT MORTALITY UNDER LABORATORY CONDITION DURING 2006 ------131 8. MEAN COMPARISON OF CHEMICAL CONTROL OF MANGO MEALYBUG FIRST INSTAR, SECOND AND THIRD INSTAR AND ADULT FEMALE UNDER FIELD CONDITION DURING 2006-2007 (AVERAGE OF BOTH YEARS) ------135 9. MEANS COMPARISON OF THE DATA REGARDING PERCENT REDUCTION OF MANGO MEALYBUG IN DIFFERENT IPM METHODS DURING 2006 TO 2008------139
iii List of Tables
10. COST BENEFIT RATIO IN DIFFEREENT TREATMENTS REGARDING CONTROL OF MANGO MEALYBUG ------140 11. COST BENEFIT RATIO ------140 12. MEAN COMPARISON REGARDING PUPAE OF MANGO MEALYBUG 900 CM 2 IN ORCHARD IN DIFFERENT PLACES DURING 2007 ------140 13. MEAN COMPARISON OF POPULATION OF ADULT MALE MANGO MEALYBUG ATTRACTED TO DIFFERENT LIGHTS DURING 2007 ------140
iv
LIST OF FIGURES
Chapter VI
FIGURE NO. TITLE PAGE NO
1. POPULATION OF MANGO MEALYBUG ON LEAVES PER 30-CM BRANCH LENGTH OF MANGO CULTIVAR CHAUNSA AT VARIOUS SIDES DURING 2005-06 AND 2006-07 ------38 2. POPULATION OF MANGO MEALYBUG ON INFLORECENCE OF MANGO CULTIVAR CHAUNSA AT VARIOUS SIDES DURING 2005-06 AND 2006-07 ------40 3. POPULATION OF MANGO MEALYBUG ON BRANCH OF MANGO CULTIVAR CHAUNSA AT VARIOUS SIDES DURING 2005-06 AND 2006-07 ------41 4. POPULATION OF MANGO MEALYBUG ON TRUNK AND WEEDS 900 CM 2 ------42 5. POPULATION OF PREDATORS, PARASITES AND FUNGUS ATTACKED NYMPHS PER 30 CM BRANCH AND 900 CM 2 ON TRUNK OF MANGO CULTIVAR CHAUNSA DURING 2005-06 AND 2006-07 ------43 6. POPULATION DYNAMIC AND WEATHER FACTORS DURING THE YEAR 2005-2006 ON CHAUNSA CULTIVAR ------44 7. POPULATION DYNAMIC AND WEATHER FACTORS DURING THE YEAR 2006-2007 ON CHAUNSA CULTIVAR ------45 8. POPULATION DYNAMIC AND WEATHER FACTORS ON CHAUNSA CULTIVAR COMMULATIVE FOR THE YEAR 2005 TO 2007 (Graphically shown) ------46 9. AVERAGE NUMBER OF EGGS LAID PER FEMALE AND AVERAGE MATING TIME WITH STANDARD DEVIATION ------67
Chapter VI
1. INITIAL AND FINAL FRUIT LOSS IN DIFFERENT CULTIVARS OF MANGO AND POPULATION OF MANGO MEALYBUG ------100
RECOMMENDATIONS
1. INTEGRATED MANAGEMENT SCHEDULE FOR MANGO MEALYBUG DROSICHA MANGIFERAE GREEN IN MANGO ORCHARDS ------155
v
LIST OF APPENDICES
APP. NO. TITLE PAGE NO
1. DATA REGARDING FIRST STADIUM DURATION ------179 2. DATA REGARDING SECOND STADIUM DURATION ------180 3. DATA REGARDING THIRD STADIUM DURATION ------181 4. DATA REGARDING FEMALE DURATION ------182 5. DATA REGARDING MALES CAME DOWN THE TREE------183 6. DATA REGARDING DISTANCE COVERED IN CENTIMETER BY FIRST, SECOND AND THIRD STADIUM IN ONE MINUTE ON TREE ------183 7. DATA REGARDING REMOVAL OF FUZZ FROM THE PUPA ONCE ------184 8. DATA REGARDING REMOVAL OF FUZZ FROM THE PUPA TWICE A TIME ------184 9. DATA REGARDING REMOVAL OF FUZZ FROM THE PUPA THRICE TIME ------185 10. DATA REGARDING NUMBER OF EGGS LAID BY FEMALES DAILY ------186 11. DATA REGARDING FIRST STADIUM LIVE WITHOUT FOOD ------187 12. DATA REGARDING SECOND AND THIRD INSTAR STADIUM LIVE WITHOUT FOOD ------188 13. DATA REGARDING ADULT FEMALE LIVE WITHOUT FOOD-189 14. DATA REGARDING TIME TAKEN BY THE MALE S FOR MATING WITH THE FEMALES ------190
vi
LIST OF ABBREVIATIONS
• Cv Coefficient of Variation • CBR Cost Benefit Ratio • Cf Crude fibre • CHO Carbohydrates • cm Centimeter • cm 2 Centimeter square • Cp Crude protein • FD Frequency of Distribution • Fig. Figure • g Gram • ha -1 Per hectare • K Potassium • LSD Least Significant Difference • M Moisture • m Meter • MMB Mango Mealybug • N Nitrogen • Na Sodium • P Phosphorus • LSD Least Significant Difference • IPM Integrated Pest Management • BZU Bahaudin Zakariya University • °C degree Celsius (=degree centigrade) • RH Relative Humidity • Av. Average
vii
ACKNOWLEDGEMENTS
All the prayers and praises are for ALMIGHTY ALLAH (Jalla- Jalalaho), The Unique, The Merciful, The Compassionate, The Provider and the source of all knowledge and guidance who never spoils the efforts. I consider it as my foremost duty to acknowledge the Omni-present kindness and love of Almighty Allah, who made it possible for me to complete the writing of this thesis. I consider it is my utmost duty to express gratitude and respect to Holy Prophet Hazrat Muhammad (SAW) and Ahlebait who are forever a torch of guidance and knowledge for humanity as a whole. I express my gratitude to my worthy supervisor Dr. Muhammad Jalal Arif, Associate Professor of Agri. Entomology, Faculty of Agriculture, University of Agriculture, Faisalabad for his keen and potential interest, valuable suggestions, consistent encouragement, dynamic supervision and sympathetic attitude during the course of this research endeavor. I feel great pleasure to express deep sense of gratitude to members of my supervisory committee Dr. Muhammad Ashfaq (T.I ), Professor and Chairman, Department of Agri. Entomology, Dr. Muhammad Aslam Khan, Professor and Chairman, Department of Plant Pathology, Faculty of Agriculture, University of Agriculture, Faisalabad, Dr. Hussnain Ali Sayyed, Department of Biotechnology, B.Z. University, Multan and Dr. Shafqat Saeed, Assistant Professor B. Z. University, Multan for their positive attitude and providing me laboratory facilities and man powers during the course of the research work. I express my heartiest gratitude and sense of obligation to Dr. Amjad Ali , Entomologist, Entomological Research Institute, AARI Faisalabad, for his skilful and marvelous guidance and positive attitude during the whole period of research. Thanks are also due to my father in law Professor (R), Malik Ghulam Asghar, their moral support and continuous encouragement, brothers and sisters in their prayers and friends, colleagues who provided technical support and facilitated in the field surveys, particularly Syed Zaffar Yab Haider (EDO), Qaisar Abbas, Zaka Sayyed and Tahir Mahmood bhatti A.O. etc. I don’t have words at command to acknowledge the moral support of my wife, Raeesa Haider, who always prayed for my success and look after children in my absence. I also pay thanks to my children, Safeer Hussain, Muneeba Haider, Najeeba Haider, M. Ammar Haider, M. Ali Haider and Labiba Haider who had to suffer the care and affection they deserved in my absence from home. Finally I apologize if I have caused anger or offence to anybody.
8
ABSTRACT
The study was conducted on bio-ecology and management of mango mealybug Drosicha mangiferae (Green) in mango orchards of Punjab Pakistan from 2004 to 2008 in District Multan, Muzzaffar Garh, Bahawalpur and Rahim yar Khan. It was concluded from the growers’ survey that among various insect pest of mango, mango mealybug was found to be the major pest followed by hoppers, fruit fly, scales, mango leaf galls Amaraemyia spp. and midges. The farmers also reported that mango mealybug caused 25-100% loss. Further the respondents indicated that ‘Chaunsa’ cultivar was the most susceptible to mango mealybug followed by ‘Fajri’, ‘Langra’ and ‘Black Chaunsa, whereas ‘Dusehri’ was resistant. Irrigation was the major source of flare up of the pest as viewed by the majority of the respondents. The practices like hoeing, ploughing, irrigation, removal of weeds, grease bands and insecticides were adapted by the respondents with variable results. The satisfaction level for the control of mango mealybug was unsatisfactory. South, East, West directions of trees showed maximum population of mango mealybug on leaves and inflorescence, whereas North direction of the plant showed minimum population. The maximum peak population of mango mealybug was observed to be 26.63 per 30-cm branch at maximum temperature of 24.64°C, minimum temperature of 10.36°C and RH 78.86%. Among twelve cultivars under study, the ‘Chaunsa’ cultivar of mango showed maximum population of mango mealybug in both the study years (104.90 and 69.83 during 2005-2006 and during 2006-2007, respectively as well as on an average of both study years (87.38), whereas ‘Tukhmi’ cultivar was found comparatively resistant with minimum population of mango mealybug i.e. 14.20, 15.86 and 18.27. On an average of both the study years, the following ranking positions towards susceptibility of mango cultivars were as under. ‘Chaunsa’ > ‘Black Chaunsa’ > ‘Malda’ > ‘Fajri’ > ‘Ratul- 12’ > ‘Langra’ > ‘Sensation’ > ‘Sindhri’ > ‘Dusehri’ > ‘Sufaid Chaunsa’ > ‘Anwar Ratul’ and >‘Tukhmi’. All the chemical plant factors on leaves and inflorescence differed significantly among various cultivars of mango. Maximum carbohydrates contents was observed in the cultivar ‘Chaunsa’ (susceptible to the pest), whereas minimum carbohydrates contents were observed in the cultivar ‘Tukhmi’ resistant to the pest. All the other factors did not show any specific sequence with the population of the pest in all the cultivars. The maximum decrease in number of fruits was recorded 11 percent on cultivar ‘Anwar Ratul’, whereas ‘Langra’ cultivar showed minimum decrease in number of fruits i.e., 3 percent over untreated trees (no control practices were applied with these trees to control mango mealybug at initial stage of the experiment). At final stage of the experiment the maximum decrease in fruits was 81 percent on cultivar ‘Chaunsa’ and minimum on cultivar ‘Tukhmi’ i.e., 22 percent. Maximum population recorded on ‘Chaunsa’ cultivar was 18/inflorescence and minimum on ‘Anwar Ratul’ was 10/inflorescence. A combination of mounds on the plastic sheet, Haider’s band and application of acetamiprid were found to be the most effective treatment resulted in 98% reduction of first instars of mango mealybug. It is further stated that the Haider’s band was the most effective and cheaper which was a new addition in the mechanical control management of mango mealybug on mango trees. The males of mango mealybug were attracted to mercury light and no males were attracted to yellow, green, red, blue lights. Male preferred to pupate in wet places near the ‘ kacha ’ (mud) water which can be exposed to sunlight by hoeing. This research project demonstrates the complete management programme for the control of mango mealybug under field condition for mango growers.
9
Chapter 1
INTRODUCTION
1.1 Agriculture in Pakistan Pakistan is located in South Asia, between the latitudes 23° 35’ to 37° 05’ North and longitudes 60° 50’ to 77° 50’ East (GOVPK, 2008). It is one of the most important agricultural countries in the world. Agriculture is the largest economic sector in the economy of Pakistan, and a dominant driving force for growth, poverty reduction and the main source of livelihood for 66 percent of the population (FBS, 2007). Agriculture sector contributes 25 percent to GDP of Pakistan. Of this vegetables and fruits contribute up to Rs. 5.4 billions /year (Himayatullah, 1999). 1.2 The importance of fruits to Pakistan Fruit is an important sector in the agriculture of Pakistan. Among the major fruits, mango occupies the second position after citrus in terms of acreage and production: date palm (42 thousand hectares), guava (47 thousand hectares), mango (86 thousand hectares) and citrus (173 thousand hectares) (Khushk and Smith, 1996). Mango is the most popular fruit amongst millions of people in the Orient, particularly in Indo-Pakistan Sub-continent. Pakistan is the 4th largest mango producer in the world (0.8 million tones) after India (10.0 million tonnes), China (1.18 million tonnes) and Mexico (1.09 million tonnes) http://www.panhwar.com/ Article79. htm. Among mango exporting countries, Pakistan is also the 4 th largest exporter of mango fruit in the world and exported about 82,059 tons, worth US$ 23.77 million during 2004 (Anonymous, 2004). Mango is one of the main foreign currencies earning fruit crop of Pakistan, but exports to many countries, especially Dubai, Saudi Arabia, United Kingdom, Germany, France, Switzerland, Holland, Singapore, Itly and Malaysia. Mango is cultivated mostly in the Punjab and Sindh provinces. But Southern Punjab is considered good for its cultivation due its favourable climatic conditions. The main mango growing districts in the Punjab province are Multan, Muzaffargargh, Bahawalpur, and Rahim yar khan. (http://www.pakissan.com/english/ allabout/orchards/
10 Chapter 1 Introduction mango/index.shtml ). More than 70 percent of the mango orchards grown in this province of Pakistan are being cultivated in Multan and Bahawalpur Divisions (Anonymous, 2002). 1.3 Importance of mango Mango ( Mangifera indica L. ) is known as “king of fruits”. It belongs to family Anacardiaceae (Singh, 1968; Litz, 1997). It is one of the most important trees on the earth and is now consumed worldwide (http://mgonline.com/mango.html). Mango is an important tropical fruit, which is being grown in more than 100 countries of the world (Sauco, 1997). But its original home is South Asia where it has been grown for the last four thousand years (Salunkhe and Desai, 1984). It is an ancient fruit of Indo-Pakistan sub-continent and is of great importance for millions (Singh, 1968; de Laroussilhe, 1980; Litz, 1997). It is nutritionally rich in carbohydrates and vitamins A and C. (http://www.pakissan.com/english/advisory/mango.diseases.andtheir.management. shtml ) and also has iron, potassium, calcium, or small quantity of protein (http://recipesnmore. blogspot.com /2007/05/ sevai.html ). Mango is a valuable ornamental plant. It is a shade tree which also protects soil against erosion and different medicinal virtues of mango are also known (D’ Almeida, 1995). After cotton and rice, mango is the third most important cash crop of Pakistan, which helps to improve livelihoods of resource poor farmers. Mango is cultivated over an area of 95,000 ha with production of 100,000 tones / annum, however, the average productivity is only 80 mounds/acre (Anonymous, 2006), which is lower than most of the mango growing countries of the world. The low yield could be attributed to different biotic constraints, as insect pests. 1.4 Insect pest of mango A number of insect pests attacked the mango crop and deprive the trees of its important nutrients. Among these pests, mango mealybug ( Drosicha mangiferae G.) is one of the destructive pests attacking the fruit trees in Pakistan (Yousuf, 1993; Prassad and Singh, 1976). In case of fruit trees, the yield is reduced severely. Tandon and Verghese 1985 reported that D. mangiferae is dangerous for mango crop. It is not only pest of mango but it attacks more than 70 other host plants (Tandon and Lal, 1978; Narula, 2003). Mango mealybug Drosicha mangiferae Green is a pest of mango and
11 Chapter 1 Introduction other orchards, known as giant mealybug (Sternorrhyncha: Coccoidea: Monophlebidae). The overall goal of this study was to develop a complete management practices against this notorious pest of mango crop. The present project consists of • Problems orientation studies • Population dynamics, cultivar resistance and biology of mango mealybug • Cultivar resistance based on biochemical analysis in leaves and inflorescence • Losses in mango yield caused by the mango mealybug • Sustainable management of mango mealybug on mango trees
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Chapter 2 REVIEW OF LITERATURE
2.1 SURVEY Conventional methods of pest management have been investigated for different crops, and used as input for development of integrated pest management packages (Norton et al., ; 1999; Bently and Baker, 2002). It is well established that evaluation of farmers’ perception and knowledge about the pests and their existing natural enemies is the important tool for the planning of campaign, research agendas and development of messages for communication (Fujisaka, 1992; Escalada and Heong, 1993). The lack of full knowledge of mango insect pests and their ecology however, is the main obstacle in pest management strategies (Van Huis and Meerman, 1997). For example, the farmers usually are unable to differentiate between the damaged caused by seed borer Deanolis aibizonalis (Hamson) from fruitflies Bactrocera dorsalis Hendel (Van Mele et al., 2001). It is also important for improving crops and plant protection to recognize those constraints which are faced by the farmers’ and their existing technical skills (Kenmore, 1991; Bentley, 1992; Morse and Buhler, 1997). 2.2 POPULATION DYNAMICS Variation in population density of phytophagous insects among conspecific trees is known to be very high (Price et al., 1990). This variation in susceptibility may be genetic, or phenotypic due to differences in environmental factors such as the nutritional status of the soil (Dale, 1988) or air pollution (Riemer and Whittake, 1989), as well as variation in plant age or seasonal phenology (Marino and Cornell, 1993). In tropical forests, for instance, a strong correlation was observed between renewal of foliage (flushing) and abundance of herbivores, especially Homoptera (Wolda, 1978). Temperature and relative humidity have been reported to play an important role in development of D. stebbingi (Singh, 1946; Yousuf and Gaur, 1993; Yadav et al., 2004). However Matokot et al., (1992) have shown that fluctuations in populations of mango mealybug ( Rastrococcus. invadens Williams. ) on mango are linked to the physiological
13 Chapter 2 Review of Literature and phenological characteristics of the host plant than to climatic factors. Seasonal changes play an important role on population fluctuations of mango mealybug (Rastrococcus invadens Williams.) its population, which decreased during the rainy season and peaked during dry season (Bovida and Neuenschwander, 1995; Dwivedi et al., 2003). 2.3 CULTIVAR RESISTANCE Host-plant characteristics may influence the herbivore’s developmental rate, and indirectly benefit natural enemies (Godfray, 1994). According to “slow-growth-high- mortality” theory of Benrey and Denno (1997), most herbivorous insects have a vulnerable stage to parasitism, and development of herbivores on a plant with weak nutritional status takes longer and thus parasitoids can take advantage of the presence of prey over a prolonged period. The host plant species on which larval development is delayed, the window of vulnerability (time spent in the first two larval instars) will be prolonged and rates of parasitism will be increased (Benrey and Denno, 1997). For example, Pereyra and Sanchez (1998) have shown that the variations in nutritional quality of host plant causes different growth rate of herbivores like budborer, Epinotia aporema feeding on these plants . Similarly Karar et al., (2007) reported that the mango mealybug ( D. mangiferae ) preferred to feed on ‘Chaunsa’ cultivar. The female mango mealybug fed on ‘Chaunsa’ (‘Sammar Bahist’) cultivar was broader and laid more number of eggs with more weight and size. The plants which show more damage are called susceptible plants and those plants which show lesser damage are called resistant. The resistance in plants is the result of interaction between two biological entities, the plant and the insect under influence of various environmental factors (Dhaliwal et al., 1993). The resistance was studied early in England on apple cultivar ‘Winter Majetin’ against wooly aphid and was found to be resistant to the woolly aphid, Eriosoma lanigerum (Hausmann). The studies have led to the development of resistant cultivars against 50 key insect pests on different crops and released world-wide. Another example of resistance in mango, the cultivar ‘mango-3’was developed which have resistance against leaf cutting weevil, Deporaus marginatus P. (Uddin et al., 2003). So the resistant cultivars are grown by the farmers and save insecticides costs which are billion dollars (Pathak and Dhaliwal, 1986; Angeles, 1991;
14 Chapter 2 Review of Literature
Dhaliwal et al., 1993; Dhaliwal and Dilawari, 1996; Carvalho et al., 1996; Salem et al., 2006). Mango cultivars grown in India and Hawaii are equally susceptible to mango seed weevil (Bagle and Prasad, 1984; Hansen et al., 1989) while, the cultivar ‘Itamaraca’ has shown some resistance to mango weevil (Block and Kozuma, 1964). 2.4 EFFECT OF HOST PLANT Host plant has great effect on the fecundity and survival of R. invadens (Bovida and Neuenschwander, 1995) for example it was observed that the population of mealybug was higher on infested trees because it has good conditions for feeding and having low escape. Further it is noted that the pre-reproductive period of mealybugs was shorter on heavily infested trees and offspring production was also higher than uninfested tree. 2.5 BIOLOGY The mango mealybug ( D. mangiferae ) nymphs started to hatch out at end of Dec. or beginning of Jan. (Chandra et al., 1987; Mohyuddin, 1989). A single female lays up to 400-500 eggs (Haq and Akmal, 1960). The duration of 1 st instar vary from 45-71 days; second 18-38 days; third instar for female 15-26 days, whereas duration for males 5-10 days. The total duration 77-135 days for female and 67-119 days for male and 78-135 for females and 77-134 days for males on mango (Rahman and Latif, 1944; Haq and Akmal, 1960) whereas on citrus the total duration was 169-304 days for female and 165-290 days for male (Saxena and Rawat, 1968). A female took 7-16 days to lay its full quota of eggs (Rahman and Latif, 1944; Chandra et al., 1987). First instars of mango mealybug D. stebbingi crawled a distance of about 40 ft and 2 nd instars 150 ft. as reported by Latif (1940). Males have ability to reconstruct the cocoon if it is damaged in any way. The copulation time of male with female was 4-10 minutes (Rahman and Latif, 1944) and the ratio of males to females was 1:19 (Chandra et al., 1987). Resistance in mango to pests has been previously reported (e.g. Hansen 1989) however additional results are needed to assess further to confirm the tolerance reported previously. Determining the tolerance to insect in mango cultivars should be performed in natural conditions. Therefore, experiment for resistance in mango against insect pest should include possible exposure of insects under different conditions. There are few reports where nutrients levels were tested in natural field conditions. For example Avilan
15 Chapter 2 Review of Literature
(1971), Singh (1978) and Hussain (2004) reported that NPK levels were the highest before flowering, fell at flowering and fruit formation but it increased again at fruit maturity. In contrast C/N ratio was the highest in flower bud differentiation and declined and remained lower in off-season in Pakistani cultivars ‘Dusehri’ and ‘Langra’ (Hussain, 2004). Similarly, Ca level was low before flowering but increased during fruit formation and lowered subsequently. Similarly, high levels of nitrogen, phosphorus and Zn were associated with off-season (Mishra and Dhillon, 1978; Chadha et al., 1984; Mishera and Dhillon, 1982). Similarly Thakur et al., (1981) shown that N, P and Ca contents were significantly higher in the leaves, which emerged from fruiting terminal but K, S and Zn contents were very low. The leaf position on the shoot, leaf age, sampling height and sampling direction could also affect the mineral contents (Chadha et al., 1981). In older leaves the K and P content decreased, while Mg, Ca, Mn and S, contents increased significantly. The P, Ca, K, Fe and Mn content changed with sampling direction, while Fe, Zn, S, Ca, Cu and K contents were significantly more in the leaves of the lower part of the tree than from the upper part. The nymphs and female scales suck sap from shoots, tender leaves and fruit peduncles but prefer to feed on inflorescence (Tandon and Lal, 1979). The affected panicles shrivel and dry. Severe infestation affects the fruit set and causes fruit drop (Khan, 1989) and this ultimately affects the yield. Yields losses due to infestations and damage caused by mealybug on mango plant can rise up to 80 percent (Entomological Society of Nigeria, 1991; Moore, 2004; Karar et al., 2007). The damage due to mealybug could be as high as 80 percent of all losses (Nwanze, 1982). Similarly Tobih (2002) observed that the infestation due to mango mealybug caused significant loss in size and weight of fresh mango fruits. 2.6 SELECTIVITY STUDIES 2.6.1 Cultural control Destruction of eggs of mango mealybug by digging them out with spades from the soil is not an encouraging practice (Rahman and Latif, 1944), whereas this way of destroying the eggs is an effective practice as reported by (Singh, 1947; Mohyuddin and Mahmood, 1993). Similarly the use of burlap band, burning of gravid females and removal of soil contaminated with eggs of mango mealybug gave complete control of
16 Chapter 2 Review of Literature mango mealybug without the use of pesticides (Sial, 1999). Burning of rubbish, scraping of soil at the bases of fruit trees and root opening are very useful practices for the destruction of eggs (Haq and Akmal, 1960). Also pruning of trees (Sandhu et al., 1980) and cutting down of damaged trees and their destruction (Agricola et al., 1989) were the most effective practices for the control of mango mealybug. Further, it was suggested that a 30 cm deep trench dug in a radius about 50 cm around tree trunk filled with decoys vegetation ideal for egg laying of Drosicha corpulenta (Hemiptera: Margarodidae ) and should be destroyed in autumn (Xu et al., 1999). 2.6.2 Mechanical control The grease band is effective for checking the migration of mango mealybug (Stebbing, 1902; Lal, 1918) whereas cotton wool dusted with DDT are effective controls (Haq and Akmal, 1960). The band prepared by using sann fibre soaked in mixture of crude oil emulsion and coal tar at the ratio of 1:1 can be quite effective for the control of Drosicha stebbingi (Dutt, 1925). Similarly Rosin + Toria oil and Rosin + Neem oil + Vaseline band were absolutely effective (Chopra, 1928; Richards and Sharma, 1934). The sticky materials used in the bands act as repellent (Latif, 1940). In the past, black oil cloth was also used as barrier for controlling the upward movement of mango mealybug, e.g. Rahman and Latif (1944) found that black oil cloth was effective against 2 nd and 3 rd instar nymphs of D. mangiferae but less effective against the nymphs of 1 st instar. Namhar bands were found effective against nymphs of mango mealybug for 51-78 days in shade, 42-58 days when partially exposed to sun depending upon climatic conditions (Lakra et al., 1980). Sand was also used as barrier for upward migrating nymphs of D. mangiferae as reported by Birat (1964). Ostico was more effective tree banding material than either Esso fruit tree grease + Coal Tar mixture for the control of D. stebbingi ( Bindra et al., 1970; Ali, 1980; Sen, 1955). Similarly, polyethylene sheeting is an effective barrier to prevent the upward moving nymphs of mango mealybug and was much cheaper, easily accessible and practical (Bindra and Sohi, 1974; Yousuf, 1993; Abrar-ul-Haq et al., 2002) whereas alkathene sheeting was more effective than polyethylene against upward crawling nymphs (Lakra et al., 1980; Tandon and Lal, 1981; Chandra et al., 1991; Narula, 2003). Double girdle band of alkathane sheeting was the more effective than single girdle alkathene bands (Srivastava, 1980 a). Plastic slippery bands were used on
17 Chapter 2 Review of Literature the base of trees against the nymphs of D. mangiferae gave best control (Sandhu et al., 1980, 1981; Singh et al., 1988 , 1991; Hashmi, 1994). Similarly, Esso tree grease bands were found to be more effective than Nimhar band against 1 st instar nymphs of the polyphagous margarodid, Perissopneum tectonae (Morr.) on guava trees (Singh, 1980) ineffective (Chandra et al., 1991). D. corpulenta is controlled by using plastic strips of 16.5 cm wide covered with a mixture of DDVP [dichlorovos] machine oil and grease in the proportion 0.5:2:5 at 1 meter above ground level and found >90 percent mortality of the pest (Chen, 1984). Khan and Ashfaq (2004) reported that Funnel Type Trap was an effective barrier for mango mealybug nymphs and also worked for collecting the egg carrying female. Further they suggested that powdered un-slaked lime was placed in the funnels to kill females which entrapped during coming down trees via stems. Machine oil and wool grease were more effective than other blocking methods (Xie et al., 2004). Karar et al., (2007) recently tested nine tree bands to check the upward movement of mango mealybug ( D. mangiferae) and found a new band named Haider’s band (plastic sheeting having a layer of 3.8 cm of grease in middle) proved most effective for the preventing insects reaching the tree canopies. 2.6.3 Chemical control The results of experiments and its analysis implies that management of this pest is more effective when the pest is in initial instars than later instars, so it would be useful to adopt the management strategies when mango mealybug is in early instars. It has already been reported by previous research workers who worked on management of this pest. The spray of insecticides parathion, Benzene Hexa Chloride (BHC) and Dichlorodiphenyltrichloroethane (DDT) was found effective against 1 st , 2 nd instar, whereas for 3rd instar nymphs and adult females Folidol, Nematox, Hanane, Diazinon and Pestox proved effective (Latif and Ismail, 1957) whereas malathion was found effective for controlling mango mealybug as told by Bindra 1967. Good control of 1st and 2 nd instar nymphs of mango mealybug i.e. 91 percent could be attained by using Formothion (Anthio) and it is decreased up to 63 percent against 3 rd instar nymphs (Atwal et al., 1969). The insecticides malathion, diazinon or dimethyldichlorovinyl phosphate (DDVP) gave best control of mango mealybug (Srivastava and Butani, 1972). Mealybugs (Maconellicoccus hirsutus Green) on mesta ( Hibiscus cannabinus ) were controlled
18 Chapter 2 Review of Literature through the application of Roger (dimethoate) or Metasystox (methyl demeton) is effective (Pushpa, 1973). High volume application of insecticides was very important to ensure coverage and reach the mealybugs in crevices and cracks on the bark, for example diazinon, quinalphos and parathion-methyl have been shown to suppress the pest quite effectively both at nymph and adult stages (Lakra et al., 1980). The chemicals like diazinon, quinalphos and parathion-methyl (methyl-parathion) were highly effective against 1 st instar nymphs that were gathered below the bands (Lakra et al., 1980). The fenitrothion was recorded as the most effective insecticides and malathion least effective for the control of mealybug, Drosicha mangiferae Green. on guava (Dalaya, 1983). Hostathion was found the effective insecticide for the control of the mealybugs Icerya aegyptiaca (Douglas) (Rojanavongse and Charernson, 1984). The carbophenothion was the most effective insecticides against gravid females and first instar nymphs of mango mealybug ( D. mangiferae) under laboratory and field conditions (Spectrum Chemical Fact Sheet). The mango pest for example mango mealybug, mango hoppers, mango shoot gall psyllid, mango fruit weevil and mango stem borer could be controlled through the application of insecticides like lebaycid, dimecron or malathion (Azim, 1985). 2.7 Sustainable Managemnet Approach for the Control of Mango Mealybug Mango mealybug ( Drosicha mangiferae Green .) is considered the most important pest of mango, so for its control, the use of chemicals should be justified and restricted. It should spare the destruction of non-target insects and useful fauna. Normally it attacks the mango trees in flowering season. Flooding in the month of Oct. often destroys the eggs buried in the soil and remaining eggs are exposed to sun heat by ploughing in the Nov. Polyethelene bands of 400 mil gauge and 25 cm width fastened around the tree trunk are another effective way of managing mealybug ascent to the trees. The sticky bands with grease material or slippery bands with alkathene or plastic sheets around the trunk at about one meter above ground level in 2 nd week of Dec. could also prevent the upward movement of nymphs (Atwal, 1963). Similarly Tandon and Verghese (1995) suggested that exposure of eggs to sun, removal of alternative host plants and conservation of natural enemies by using garlic oil or neem seed extract around the trunk of trees and application of alkathane bands could also eliminate mango mealybug
19 Chapter 2 Review of Literature population. Bajwa and Gul (2000) reported that Drosicha stebbingii could be managed through destruction of eggs, banding of trees and spray of insecticides v.z., Bulldock 25EC, Endon 35EC and Mepra 50EC on trees of Paulownia tomentosa and Paulownia fortunei. Whereas, Jia et al., (2001) achieved good control of Drosicha corpulenta, a walnut pest through dusting parathion in micro capsules form or phoxim on the ground before the soil freezes in winter, painting mixture of 1 kg omethoate + 5 kg mineral oil and spraying 300 times, solution of Bt (Bacillus thuringiensis ) or a 2000- times solution of 20% fenpropathrin from mid Feb. to mid Mar. for the control of nymphs. The application of insecticides like Mepra 50EC and Endon 35EC along with banding tree trunks, ploughing soil to destroy eggs could also be an effective strategy for mealybug control (Gul et al., 1997). Insecticides and parasitoids together could also be an important strategy to manage mealybug. For example, prepupal parasites have been shown to parsitoids female of D. mangiferae (Kalia, 1995). Ishaq et al., (2004) worked on the management of mango mealybug (D. stebbingi ) and concluded that the mortality only with insecticide sprays were up to 55 percent, whereas sticky bands along with burying and burning treatments significantly reduced the extent of infestation by mango mealybug (0.00-15.79 percent) and burlap bands reduced population of mango mealybug nymphs by 78.98 percent. So it was concluded that for the control of mealybug integration of insecticides with bands along with burning and burying treatments gave good control.
20
ABSTRACT
About 141 mango growers’ were interviewed during peak activity of mango mealybug in southern Punjab, Pakistan during 2004-05, to know the farmers’ knowledge, perceptions and practices in the management of mango mealybug. It was observed during survey that most of the farmers (94.3 percent) reported that Chaunsa cultivar (king of all mango cultivars) was susceptible to mango mealybug and irrigation water was the major source of flare up of this pest. Diazinon and methidathion were the most commonly used insecticides as 72.9 and 51.8 percent farmers gave positive response and grease bands were applied for the control of mango mealybug by the majority of the respondents. Hundred percent yield losses was told by 22.7 percent respondents whereas 75 percent, 50 percent and 25 percent losses were reported by 39.7, 31.9 and 14.2 percent respondents, respectively. Burning of females, application of grease bands and insecticidal spray did not show satisfaction to the respondents for the control of fertilized females of mango mealybug coming down from the trees. Lack of knowledge about the pest, lack of money, adulteration and shortage of pesticides, lack of unity amongst farmers and small land holdings were the main constraints for the control of mango mealybug. The observations made in the field corroborated the views of farmers regarding spread of this pest through irrigation water. Key words: Mango, Indigenous knowledge, Drosicha mangiferae , Pest management.
21 Chapter 3 Problem Orientation Studies
3.1 INTRODUCTION
The mango crop is attacked by 500 insect pests due to the vast range of agro- ecosystems and climatic conditions in which it is grown (Tandon and Varghese, 1985). However, the severity of the pest can be identified through the growers’ survey to develop management practices. Knowledge of pests varies from farmer to farmer and to identify farmers’ problems and their existing knowledge, surveys are considered important. The biggest constraints in the establishment of an Integrated Pest Management program is lack of proper information about growers’ knowledge and perceptions, mango pests and their ecology and practices in pest management (Morse and Buhler, 1997; Teng, 1987; Heong, 1985). There is a need to integrate the farmer’s techniques and their indigenous knowledge about the insect pest in the development processes to improve farmers’ pest management practices (Nyeko et al., 2007). The growers have two advantages over scientists, a life-long experience of growing their crops, a the system of passing their knowledge to the next generations through exchange of information, that has been built up through regular observations through informal and formal actor networks (Van Mele and Van Chien, 2004). However, some scientists disagree with these findings and their point of view is that scientist are trained to test the validity of conclusions without bias, whereas growers generally have a great deal of bias in the way they interpret results (Toews, 2010, per. com.). The present survey was therefore conducted with the objective to identify the insect pest problems at farmers’ fields. The main aims of the survey were (i) To identify the insect pests problem in mango orchards (ii) To determine and identify the most serious pest of the mango orchards (iii) To determine the infestation of the most serious pest and identify the problems faced by growers to manage the pest (iv) To identify the alternate host plants and the means of dispersal of the most serious pest (v) To compare the recommended and farmers’ adapted management strategies for the most serious pest
22 Chapter 3 Problem Orientation Studies
3.2 MATERIALS AND METHODS
3.2.1 STUDY SITES AND ITS CLIMATE Multan Muzzaffargarh Bahawalpur R.Y.Khan Latitude 30-12N 30-12 N 29-25 N 29-12 N Longitude 71-30 E 71-14 E 71-4 E 70-30 E Altitude (ft) 0121 0124 0115 0120 Mean Annual Temp (°C) 26.50 26.50 26.50 26.00 Mean Annual 168 160 162 160 Rainfall (mm)
A survey was conducted in the main mango growing districts of the Punjab province (Pakistan) and the results were used to set the research objectives. 3.2.2 Preliminary Survey In the preliminary survey, 25 (n=25) mango growers were selected randomly, during Dec., 2004 to know farmers’ knowledge, perceptions and practices regarding insect pest problems of mango crops in district Multan. A short list of questions was prepared to collect information and to identify the major insect pests of mango orchard in mango growing areas of Punjab. 3.2.3 Comprehensive Survey. After the preliminary survey, a questionnaire was revised for conducting a comprehensive and detailed survey during Jan., 2005 in the major mango growing districts of the Punjab viz., Multan, Muzzaffar Garh, Bahawalpur and Rahim Yar Khan. The mentioned districts of southern Punjab are considered a favourable for its cultivation and higher yield. In the preliminary survey mango mealybug was identified to be a serious pest of mango orchard in southern Punjab therefore a detailed and comprehensive survey was planned to identify the reasons for its spread and establishment as a serious pest of mango. The questionnaire was prepared to achieve the following major objectives.
23 Chapter 3 Problem Orientation Studies
• To determine the mango mealybug infestation and the major problems in management being faced by the mango growers of the Punjab. • To know alternate host plants and the means of dispersal of mealybug to other host plants. • To compare the recommended and farmer’s adopted management strategies for mango mealybug. In this study, only those growers were interviewed whose mango trees were infested with mango mealybug. A total of 141 (n=141) mango farmers were interviewed. The information regarding the attack of this pest was collected from the Department of Pest Warning and Quality Control, Agriculture Extension, Ayub Agricultural Research Institute, Faisalabad and persons related to the purchase of mango in markets, pesticides dealers, contractors, nursery growers and fellow farmers in different districts. To evaluate farmer’s perception, they were first asked about the most important insect pest problems of mango crop including major pests, pest incidence, pest severity, estimated yield losses and management practices to control the insect pests. Interviews were conducted either in the farmer’s house or in their orchards. Each farmer was interviewed for 25-30 minutes. The survey data were encoded, entered into Excel sheets and verified prior to analysis. SPSS program (release 10 for windows) (Bryman and Cramer, 2001) was applied for used to calculate the frequency distributions of of the responses.
24 Chapter 3 Problem Orientation Studies
3.3 RESULTS AND DISCUSSION
The study was comprised of the problems of insect pests in the mango orchards and farmer’s views regarding various aspects relating to their mango cultivars in relation to resistance susceptibility against insect pests, particularly mango mealybug, its mode of spread, hibernation places, comparison of recommended and farmer’s management practices and losses caused by the insect pests. The study was conducted in two phase viz., preliminary survey and comprehensive survey. The results are described below: 3.3.1 PRELIMINARY SURVEY The study was conducted in district Multan with the following objectives. a) To know awareness among farmers about insect pests of mango. b) To observe the most damaging insect pests in term of yield losses. c) To identify the reasons of seriousness of the pest.
3.3.1.1 Awareness among Farmers about Insect Pests. The results (Table 1) reveal that amongst the respondents, 88 percent knew about the mango mealybug followed by 80 percent who had the knowledge each about hoppers and fruit fly. The minimum awareness was 8 percent only. Amongst the respondents, 44 percent and 24 percent of the farmers indicated that they knew about scales and mango midges, respectively. From these results, it was observed that the greatest proportion of respondents knew about the mango mealybug and thus this species was considered to be the most important insect pest of mango.
25 Chapter 3 Problem Orientation Studies
Table 1. AWARENESS OF THE RESPONDENTS ABOUT DIFFERENT INSECT PESTS OF MANGO
Yes Name of Insect F.D. Percent English Name Scientific Name Mango Hoppers Ideoscopus clypeaus 20 80 Mango Mealybug Drosicha mangiferae 22 88 Fruitfly Dacus dorsalis 20 80 Mango Scale Radionaspis indica 11 44 Mango leaf Galls Amaraemyia spp. 6 24 Mango Midges Erosomyia indica 2 8 n=25 F.D. Signifies Frequency Distribution
3.3.1.2 Relationship between Pest and Yield Losses The results regarding the farmers’ views about the relationship of the pests and yield losses are shown in Table 2. The 40 percent respondents indicated that 100 percent losses occurred due to the attack of mango mealybug, while 32, 20 and 8 percent respondents reported 75, 50, and 25 percent losses, respectively. The fruitfly was ranked as the second major insect pest as 8, 40 and 52 percent respondents 75, 50 and 25 percent losses, respectively occurred due to this pest. The mango hoppers were ranked as the third major insect pest as viewed by 36 and 64 percent respondents reported 50 and 25 percent losses occurred due to this pest, respectively. The losses caused by scales, galls and midges were up to 25 percent each as reported by 100 percent respondents. From these results it was again observed that mango mealybug was the most serious pest as reported by the majority of the respondents and that this pest caused the greatest losses to mango fruits.
26 Chapter 3 Problem Orientation Studies
Table 2. PEST WISE EXTENT OF DAMAGE TO MANGO FRUIT AS TOLD BY THE RESPONDENTS
Name of Insect Extent of Damage as viewed by the Respondents 25 Percent 50 Percent 75 Percent 100 Percent English Scientific Name Name FD percent FD percent FD percent FD percent Mango Ideoscopus 16 64 9 36 0 0 0 0 Hoppers clypeaus Mango Drosicha 2 8 5 20 8 32 10 40 Mealybug mangiferae Fruitfly Dacus 13 52 10 40 2 8 0 0 dorsalis Mango Radionaspis 25 100 0 0 0 0 0 0 Scale indica Mango Amaraemyia 25 100 0 0 0 0 0 0 leaf Galls spp Mango Erosomyia 25 100 0 0 0 0 0 0 Midges indica n=25 F.D. Signifies Frequency Distribution
3.3.1.3 Dominance Factors of Mango Mealybug The results regarding dominance factors responsible for the spread of mango mealybug are given in Table 3. It is evident from the results that 84 percent respondents told that the pest spread quickly due to high fecundity rate as compared to other mango pests. The majority of the respondents (92 percent) told that the pest was very difficult to control. The other factors were observed that 64 percent farmers told that they had no knowledge about the pest, whereas 76 percent and 80 percent respondents told about ineffective insecticides and many places of hibernation, respectively. Table 3. VIEWS OF THE RESPONDENTS REGARDING MANGO MEALYBUG AS A VERY SERIOUS PEST
Yes Reasons FD Percent Spread quickly due to high fecundity 21 84 Difficult to control 23 92 Lack of information 16 64 Non-effective spray 19 76 Hibernate in different places 20 80 n=25 F.D. Signifies Frequency Distribution
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CONCLUSION Mango mealybug was the most serious insect pest and the problem is becoming serious more due to high fecundity, lack of knowledge about the pest among respondents, ineffective insecticides and multiple hibernation places. 3.3.2 COMPREHENSIVE SURVEY Keeping in view the problems faced by mango growing farmers’ in managing mango mealybug infestation as observed during preliminary survey, a comprehensive and detailed survey was conducted with the objective to confirm the previous results by extending the study for four major mango growing districts of the Punjab viz., Multan, Bahawalpur, Rahim yar Khan and Muzaffargarh during Jan. to Feb. 2005. The results are presented under the following sub-sections. 3.3.2.1 Respondent's knowledge about resistant and susceptible cultivars of mango The awareness of the respondents regarding susceptible/resistant mango cultivars against mango mealybug is shown in Table 4. Among the respondents, 94 percent reported ‘Chaunsa’ cultivar, as the most susceptible, 3 percent told the resistant and 3 percent had no reply. Furthermore, ‘Fajri’ and ‘Langra’ were ranked the next most susceptible cultivars according to 69 percent and 63 percent respondents, respectively. According to the survey, 63 percent of respondents had the view that ‘Black Chaunsa’ was also found susceptible, whereas 14 percent told this cultivar was resistant to mango mealybug. Majority of the respondent did not know about the susceptibility and resistant response of mealybug to other cultivars of mango to the mealybug. The 57 percent respondents reported ‘Hydershahwala’ as mealybug resistant genotype followed by ‘Dusehri’, ‘Sufaid Chaunsa’, ‘Sanglakhi’ and ‘Langra’ by the view of 62, 48, 32 and 31 percent respondents, respectively. According to the opinion of the majority of respondents (94 percent) ‘Chaunsa’ is a susceptible genotype to mango mealybug.
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Table 4. AWARENESS AMONGST THE RESPONDENTS REGARDING SUSCEPTIBILITY AND RESISTANCE MANGO CULTIVARS AGAINST MANGO MEALYBUG.
Name of Susceptible Resistant Not Known Cultivars FD Percent FD Percent FD Percent Langra 89 63 44 31 8 6 Dusehri 48 34 88 62 5 4 Chaunsa 133 94 4 3 4 3 Fajri 97 69 12 9 32 23 Malda 32 23 65 46 44 31 Anwar Ratul 32 23 57 40 52 37 Muhammadwala 29 21 8 6 104 74 Khangarhribacha 0 0 24 17 117 83 Sindhri 33 23 32 23 76 54 Alphanso 0 0 17 12 124 88 Sanglakhi 20 14 45 32 76 54 Sobhawali ting 28 20 40 28 73 52 Hydershahwala 52 37 80 57 9 6 Zafrani 16 11 4 3 121 86 Sensation 28 20 16 11 97 69 Chanwal 4 3 20 14 117 83 Tukhmi 12 9 40 28 89 63 Black Chaunsa 89 63 20 14 32 23 Sufaid Chaunsa 53 38 68 48 20 14 Ratul-12 26 18 8 6 107 76 n=141 F.D. Signifies Frequency Distribution
3.3.2.2 Awareness Regarding Methods of Spreading of Mealybug The results regarding awareness among the farmers about methods of spreading of mango mealybug are presented in Table 5. The majority of the respondents i.e. 94 percent told that irrigation water is the main source of dispersal of mango mealybug, while 49
29 Chapter 3 Problem Orientation Studies percent respondents opined that mango mealybug spread through nursery plants and transportation by machinery. The other methods of spreading cited by respondents included spread from affected branches of inflorescence by malformation, by walking of insects, farm yard manure, dissidence, migration from one plant to another. However, the dispersal of mealybugs through weeds by human being cannot be ignored as 29, 52, 11, 33, 41 and 28 percent respondents had positive views about it. None of the respondent reported birds as active spreaders of mango mealybug. Table 5. AWARENESS AMONGST THE RESPONDENTS REGARDING METHOD OF SPREADING OF MANGO MEALYBUG
Yes Methods of spreading FD Percent Through irrigation water 133 94 Through nursery plant 69 49 Through Air 25 18 Transportation by machinery 69 49 Through Birds 0 0 Through destroyed malformed inflorescence 41 29 By walking 74 52 Through Farm Yard Manure 15 11 Through dissidence 47 33 Plants to plants 58 41 Through weeds taken by woman 39 28 n=141 F.D. Signifies Frequency Distribution * Dissidence- The enmity or evil intention of one person or family to other person or family to inflict loss to his enemy’s orchard.
3.3.2.3 Awareness Among Respondents Regarding Hibernation Places of Mango Mealybug. According to survey results on hibernation of mango mealybug (Table 6) reveal that 83 percent respondents had the view that the places under mango trees were the most favorable sites for hibernation followed by cracks in trees (68 percent respondents) and mud walls around orchards (57 percent respondents). Amongst the respondents 43, 22, 17 and 17 percent indicated that mango mealybug hibernates in soil under tree
30 Chapter 3 Problem Orientation Studies
canopy, roots of plants, kacha (mud) water channels and under the fallen leaves, respectively. Table 6. AWARENESS AMONGST THE RESPONDENTS REGARDING PLACES OF HIBERNATION OF MANGO MEALYBUG
Yes Places FD Percent Under tree near trunk 117 83 Mud wall around orchards 80 57 Cracks in tree 96 68 Soil under tree canopy 61 43 Kacha (mud) water channel/kacha road 24 17 Under leaves 24 17 In roots of plants 31 22 n=141 F.D. Signifies Frequency Distribution
3.3.2.4 Practices Adapted by the Farmers for the Control of Mango Mealybug 3.3.2.4.1 Cultural Practices The cultural management practices adapted by the farmers to control mango mealybugs are given in Table 7. The practice of removal of weeds was adapted by the majority of the respondents i.e. 60 percent. However, 50, 48, 34 and 13 percent of farmers used hoeing, irrigation, removal of eggs and ploughing as the major mango mealybug management practices, respectively. From these results it is concluded that removal of weeds was adopted by the majority of the respondents for the control of mango mealybug. The results regarding to the satisfaction of respondents relating to control practices adapted so far reveal that 18 respondents had the view that hoeing practices controlled the mango mealybug up to 50 percent while seven, six and twenty farmers had the views that ploughing, irrigation and removal of eggs also resulted in 50 percent control. The practice adapted by the majority of the respondents regarding removal of weeds showed that 85 respondents had the view that this practice resulted in 25 percent control of mango mealybug. Twenty one respondents satisfied 75 percent control of mango mealybug by adapting removal of eggs. From these results it was
31 Chapter 3 Problem Orientation Studies
observed that the practices adapted by the farmers did not give satisfactory control of mango mealybug. Table 7. AWARENESS AMONGST THE RESPONDENTS REGARDING CULTURAL PRACTICES OF MANGO MEALYBUG
Yes Satisfaction Practices 75 100 FD Percent 25 percent 50 percent percent percent Hoeing 71 50 53 18 0 0 Ploughing 19 13 12 7 0 0 Irrigation 67 48 61 6 0 0 Removal of weeds 85 60 85 0 0 0 Removal of eggs 48 34 7 20 21 0 n=141 F.D. Signifies Frequency Distribution
3.3.2.4.2 Mechanical Practices The views of the respondents regarding mechanical practices adopted by them and their satisfaction level for the control of mango mealybug are presented in Table 8. The results reveal that grease bands were adopted by majority of the respondents i.e. 89 percent and 43 respondents told that this practice controlled the mango mealybug up to 25 percent while 82 respondents reported up to 50 percent control of this pest. The second most common practice was the application of plastic sheet bands which was adopted by 43 percent respondents and 29 farmers told that this practice controlled the pest up to 25 percent while 32 farmers had the view that this practice depressed the pest population up to 50 percent. The application of gunny bags and cotton bands were not adopted by any respondent. Non recommended practices i.e. the application of mud bands, daily spray, spreading of insecticides and use of calcium carbonate were also adopted by the some of the farmers and showed unsatisfactory control of mango mealybug.
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Table 8. AWARENESS AMONGST THE RESPONDENTS REGARDING MECHANICAL PRACTICES OF MANGO MEALYBUG
Yes Satisfaction Practices 25 50 75 100 FD Percent percent percent percent Percent Plastic sheet bands 61 43 29 32 0 0 Grease bands 125 89 43 82 0 0 Cotton bands 0 0 0 0 0 0 Black oil cloth bands 20 14 7 13 0 0 Gunny bangs 0 0 0 0 0 0 Mud bands 12 9 12 0 0 0 Daily spray 40 28 3 29 8 0 Spread insecticides 12 9 0 8 4 0 Use of calcium carbonate 8 6 6 2 0 0 n=141 F.D. Signifies Frequency Distribution
From these results, it was observed that none of the mechanical control adopted by the respondents gave complete control of mango mealybug. 3.3.2.4.3 Response of Chemical Insecticides The results regarding the awareness amongst the respondents regarding chemical control of mango mealybug are given in Table 9. Diazinon (Basudin)was used abundantly by 100 (73 percent) respondents for the control of mango mealybug followed by methidathion (Supracide)73 (52 percent). About the satisfaction level it was observed that 86 respondents reported 75 percent control whereas 14 respondents told 100 percent control with the three sprays of diazinon. Regarding the application of methidathion, 52 percent respondents replied the answer whereas 48 percent did not know. Forty one respondents replied that the application of methidathion gave 50 percent control whereas 12 and 20 respondents reported 75 percent and 100 percent control respectively. The application of triazophos (Hostathion), methyl parathion, deltamethrin (Decis), fenpropathrin, lambdacyhalothrin (Karate), methamidophos, malathion, bifenthrin (Talstar), fenvalerate (Sumicidin), DDT, cypermethrin + profenophos (Polytrin-C), monocrotophos (Nuvacron), fenpropathrin (Danitol), chlorpyrifos (Lorsban), carbofuran (Furadon) and Kerosine oil are being used for the control of mango mealybug and resulted in unsatisfactory control as reported by the respondents. The majority of the
33 Chapter 3 Problem Orientation Studies respondents did not know about these insecticides. The number of respondents, who gave a positive response, ranged from 3 to 29 percent. According to the results it was observed that none of the insecticides fulfilled the desire satisfaction of the respondents. Table 9. AWARENESS AMONGST THE RESPONDENTS REGARDING CHEMICAL CONTROL OF MANGO MEALYBUG
Yes No of Satisfaction Chemical used 25 50 75 100 FD Percent spray percent percent percent Percent Diazinon 100 73 3 0 0 86 14 Methidathion 73 52 4 0 41 12 20 Triazophos 41 29 4 13 24 4 0 Methyl parathion 28 20 2 0 10 18 0 Deltamethrin 8 6 3 0 2 6 0 Fenpropathrin 24 17 4 10 14 0 0 Lambdacyhalothrin 32 23 3 0 14 18 0 Methamidophos 25 18 4 2 18 5 0 Malathion 16 11 1 0 7 9 0 Bifenthrin 16 11 3 2 11 3 0 Fenvalerate 4 3 4 0 1 3 0 DDT 8 6 2 0 0 8 0 Cypermethrin+ 8 6 3 0 2 8 0 Profenophos Monocrotophos 24 17 4 0 7 17 0 Fenpropathrin 8 6 3 0 2 6 0 Chlorpyrifos 16 11 4 0 3 11 2 Carbofuran 4 3 1 0 1 3 0 Kerosine oil 4 3 1 0 0 4 0 n=141 F.D. signifies Frequency Distribution
3.3.2.5 Practices Adopted by the Farmers to Control the Fertilized Female of Mango Mealybug Coming down the Tree The results, given in Table 10 shows the awareness amongst the respondents’ practices, regarding fertilized females of mango mealybugs coming down from the tree. For the control of coming down females of mango mealybug, 38 percent respondents had positive view for burning the female, 17 percent for grease bands and 17 percent for
34 Chapter 3 Problem Orientation Studies insecticides spray, whereas 62, 83 and 83 percent, respondents’ replied negative views for burning the female, grease bands and insecticides spray, respectively. The practice of burning the females gave 50 percent satisfactory control as reported by 8 respondents. The satisfaction level was found to be zero for various levels of control in all the control methods. Table 10. AWARENESS AMONGST THE RESPONDENTS PRACTICES REGARDING FERTILIZED FEMALE OF MANGO MEALYBUG COMING DOWN THE TREE.
Yes Satisfaction Practices 25 50 75 100 FD Percent percent percent percent percent Burning the females 53 38 45 8 0 0 Grease bands 24 17 24 0 0 0 Spray insecticides 24 17 24 0 0 0 n=141 F.D. Signifies Frequency Distribution 3.3.2.6 Yield Losses by Mango Mealybug. The views of the respondents regarding yield losses by mango mealybug are given in Table 11. Among the respondents, 35 percent told that mango mealybug caused up to 75 percent yield losses, whereas 14, 28 and 23 percent respondents had the view that mealybug cause 25, 50 and 100 percent yield losses, respectively. From these results, it is concluded that mango mealybug is a very serious pest of mango orchards and can cause 100 percent yield losses. Table 11. AWARENESS AMONGST THE RESPONDENTS REGARDING LOSSES IN YIELD OF MANGO MEALYBUG
Losses in yield by Mango FD Percent Mealybug 25 percent 20 14 50 percent 39 28 75 percent 50 35 100 percent 32 23 n=141 F.D. Signifies Frequency Distribution
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3.3.2.7 Major Problems Faced by the Farmers The results regarding the problems faced by the farmers are presented in Table 12. According to 68 (48 percent) respondents, lack of knowledge about the pest was the major problem. The other problem faced by the farmers were lack of money 44 (31 percent), lack of sprayer 16 (11 percent), shortage of pesticides 22 (16 percent), lack of unity interest 28 (20 percent), eggs spread in wide areas 39 (28 percent), costly control measures 24 (17 percent), small land holding 23 (16 percent) and adulterated pesticides 29 (21 percent) and fellow farmers donot spray 24 (17 percent). It was further observed that 77(55 percent) respondents had the view that no control measure was adopted for the control of mango mealybug. Table 12. AWARENESS AMONGST THE RESPONDENTS REGARDING MAJOR PROBLEMS FACED BY MANGO GROWERS.
Yes Problems FD Percent Lack of money 44 31 Lack of sprayer 16 11 Lack of knowledge 68 48 Shortage of pesticides 22 16 Lack of unity interest 28 20 Eggs widely spread 39 28 No attention after entering the soil 28 20 Costly control measures 24 17 Small land holding 23 16 Adulterated pesticides 29 21 Fellow farmers don't spray 24 17 No control measures 77 55 n= 141 F.D. Signifies Frequency Distribution
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3.4 DISCUSSION
A survey was conducted regarding the views of respondents relating to the awareness among farmers about insect pests of mango, to determine growers’ perceptions of the most damaging insect pests and the seriousness of the pest, their knowledge of resistance and susceptible cultivars of mango and their awareness regarding methods of spreading of mango mealybug. The survey results also determined the growers’ knowledge of the hibernation places of the mealybug, mealybug control practices and yield losses caused by mango mealybug. The results revealed that majority of the respondents i.e. 88 percent were aware that mango mealybug was a pest followed by mango hopper (80 percent), fruit fly (80 percent), scale insect (44 percent), galls (24 percent) and mango midges (8 percent). Furthermore 40 percent of the respondents had the view that the mango mealybug damaged the fruit up to 100 percent. However, 32 percent indicated a 75 percent loss, 20 percent indicated a 50 percent loss and 8 percent indicated a 25 percent loss, respectively. In case of other insect pests, the extent of damage was viewed as less important and lower in value. The seriousness of mango mealybug according to the respondents was due to spread, dispersal of the pests and difficulty in control, lack of information, non effective insecticides and hibernation of the pest in different places. ‘Chaunsa’ cultivar of mango was the most susceptible as indicated by maximum respondents i.e. 94 percent as compared to all the other mango cultivars. Irrigation water is the major source of spreading of mango mealybug as indicated by the majority of the respondents i.e. 94 percent. The present observations made in the field corroborated with the views of farmers regarding spread of this pest. However, some scientists have viewed that every person may not have experience with all of these cultivars. These responses are likely biased toward more common cultivars (Toews, 2010, per. com.). However, 49, 17, 49, zero percent, respondents have the viewed that mango mealybug spread through nursery plants, through air, through transportation of machinery, through birds, through malformed flowers (removed from the trees by growers), by walking, through farm yard manure, through dissidence
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(enmity), through plant to plant and through weeds taken by peoples weeding in the field has been reported by 30, 52, 11, 33, 41, and 28 percent respondents. Majority of the respondents i.e. 83 percent has reported that the mango mealybug hibernated under tree near trunk followed by cracks entries (68 percent), mud walls around orchards (57 percent), soil under tree canopy (43 percent), roots of the plants (22 percent), sides of kacha water channel (17 percent) and under leaves (17 percent). None of the cultural and mechanical practices gave 100 percent satisfaction regarding control of mango mealybug to the respondents. Amongst various insecticides Basudin was found to be the most effective as 86 and 14 respondents reported 75 and 100 percent control of mango mealybug. Majority of the respondents i.e. 35 percent had the view that mango mealybug caused losses up to 75 percent, whereas 14, 28 and 23 percent respondents had the view that mango mealybug caused losses to mango fruits up to 25, 50 and 100 percent, respectively. No control measure adopted by the farmers for the control of mango mealybug as viewed by 55 percent respondents was the major constraint. The other major constraint was the lack of knowledge (48 percent respondents) about the pest amongst the farmers. The other problems as pointed out by the respondents are the lack of money (31 percent), eggs widely spread (28 percent), adulterated pesticide (21percent), lack of unity interest, no attention after entering the soil (20 percent), costly control measures fellow farmers don’t spray (12 percent), small land holding (16 percent), shortage of pesticides (16 percent) and lack of sprayers (11 percent). The results indicated that the lack of knowledge about the pest amongst farmers, poverty, small land holding, lack of unity amongst the farmers were the main constraints for the formulation of effective IPM strategy. The present findings can be compared with those of (Van Mele et al., 2001; Heong, 1985; Teng, 1987; Morse and Buhler, 1997). It is necessary to improve the communication system, develop messages and plan campaigns for the effective control of insect pests of mango especially mango mealybug to improve the knowledge of the farmers for perception of pest and natural enemies (Fujisake, 1992, Escalada and Heong, 1993). The work on the same aspects have so far been conducted by (DOA and DOAE, 1995; PCARRD, 1994; Waite, 1998; Ochou et al, 1998; Pollard, 1991; Trutmann et al., 1993, 1996; Burleigh et al., 1998; Van Huis et al.,
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1982; Atteh, 1984; Chitere and Omolo, 1993; Bottenberg, 1995; Raheja, 1995; Kemmore, 1991; Bentley, 1992; Morse and Buhler, 1997; Van Mele et al., 2002). Furthermore, according to the present survey the majority of the respondent indicated that mango mealybug is the major pest of mango and caused 100 percent loss to mango fruits. These findings can be compared with those of Bokonon-Ganta et al., (2001). The results of the current survey show that the majority of the respondents knew something about mango mealybug, mango hoppers and fruit flies, whereas the minority of the respondents has little information about other insects of mango like scale, galls and mango midges. One hundred percent loss in mango fruits caused by mango mealybug was reported by 40 percent respondents whereas, zero percent of respondents observed losses caused by other insects. Non-effective insecticides, rapid spread, ability to hibernates in different places, difficulty to control and lacks of information about mango mealybug are the main reasons for the need to formulate of an effective IPM strategy. The cultivar ‘Chaunsa’ was the most susceptible to mango mealybug as viewed by the majority of the respondents. A little information on insect pests of mango especially mango mealybug through survey was sorted out but it was concluded that mango mealybug was the major constraint among the growers and the information obtained from the growers were used in developing IPM package for sustainable management of mango mealybug. • 100 percent yield losses was told by 23 percent respondents whereas 75 percent, 50 percent and 25 percent losses were reported by 35, 28 and 14 percent respondents, respectively • Burning of females scales, application of grease bands and insecticidal sprays did not give satisfactory results to the respondents for the control of fertilized females of mango mealybug migrating or dispersing down from the trees
39
ABSTRACT
The study was conducted on population dynamics, cultivar resistance and biology of mango mealybug. Regarding population of mango mealybug it was observed that the South, East, West directions of trees showed maximum population of mango mealybug on leaves and inflorescence, whereas North direction of the plant showed minimum population. The maximum peak population of mango mealybug was observed to be 26.6 per 30-cm branch at maximum temperature of 24.6°C, minimum temperature of 10.4°C and RH 78.9 percent. Among twelve cultivars under study, the ‘Chaunsa’ cultivar of mango showed maximum population of mango mealybug in both the study years (104.9 and 69.8 during 2005-2006 and during 2006-2007, respectively as well as on an average of both study years (87.4), whereas ‘Tukhmi’ cultivar was found comparatively resistant with minimum population of mango mealybug i.e. 14.2, 15.9 and 18.3. On an average of both the study years, the following ranking positions towards susceptibility of mango cultivars were as under. ‘Chaunsa’ > ‘Black Chaunsa’ > ‘Malda’ > ‘Fajri’ > ‘Ratul-12’ > ‘Langra’ > ‘Sensation’ > ‘Sindhri’ > ‘Dusehri’ > ‘Sufaid Chaunsa’ > ‘Anwar Ratul’ and >‘Tukhmi’. First instar male and female duration on an average is 56.3 days whereas 2 nd instar has 26 days. In case of 3 rd instar female has duration 19.5 days and male has 3 days. Male has pupal stage while it is absent in female. Key words: Drosicha mangiferae , Population dynamics, Cultivar resistance, Biology
40 Chapter 4 Population Dynamics, Cultivar Resistance & Biology
4.1 INTRODUCTION
There are ca 1,000 different cultivars of mangoes throughout the world but Pakistan offers a wide choice of ca 3500 mango cultivars (Anonymous, 2008). The most famous and commercial cultivars of mango which are grown on large scale, those cultivars are ‘Sindhri’, ‘Dusehri’, ‘Chaunsa’ (‘Summer Bahist’), ‘Black Chaunsa’, ‘Sufaid Chaunsa’, ‘Fajri’, ‘Malda’, ‘Sensation’, ‘Anwar Ratul’, ‘Ratul-12’ and ‘Langra’. All these cultivars differ in taste and flavour. These are also different in shape and size. Mango is one of the most extensively exploited fruits used for food, juice, fragrance and color. Antibiosis, Antixenosis and tolerance are three modalities of host plant resistance (Painter 1951, Kogan and Ortman 1978, Panda and Khush 1995).Antibiosis (causes harmful effects on insect life cycle) is one form of host plant resistance the other forms are antixenosis resistance (where the pest is unable to locate or colonize a host) and tolerance (where the plant does not suffer from the presence of pest). Plant resistance to insect pests is one of the best components among various tactics of IPM. It is the result of interactions between the insects and plants that the environment conditions under which a plant grown is not favourable for the development and growth of the insects that are associated with the plants. As this approach is environment friendly, so it is regarded as the key to integrated pest management. It also provides cumulative protection to insect pests and is also compatible with other pest management practices. During the last two decades, great progress has been made in the development of resistant cultivars to major insect pests of crops (Dhaliwal and Singh, 2004). Resistance is a heritable characteristic that enables a plant to inhibit the growth of insect population or to recover from the damage caused by populations that were not inhibited to survive (Kogan, 1982). The genetic properties of a cultivar to hinder the activities of insects so as to minimize percent reduction in yield as compared with other cultivars of the same species under similar condition (Dhaliwal et al., 1993). Abiotic factors have an important influence on the survival, development and
41 Chapter 4 Population Dynamics, Cultivar Resistance & Biology reproductive capacity of insect pests and were considered the main cause of fluctuations in animal population (Elton, 1927). Andrewartha and Birch (1954) further highlighted the role of climatic factors on the basis of detailed research into population dynamics, distribution of swarm-forming grasshopper and apple blossom thrips and concluded that the populations were entirely governed by climatic factors. Abiotic factors such as temperature, relative humidity and rainfall play an important role in the population fluctuation. For example, Atwal and Singh (1990) reported that some insects go under aestivation, hibernation and diapause to overcome the periods of unfavourable temperature in their life cycle. Similarly moisture has adverse effects on insects for example it encouraged disease outbreaks and also effect on reproductive capabilities of most of the insects (Dhaliwal and Arora., 1998). Studies were conducted on mango mealybug for population dynamics, varietal resistance and biology with the following objectives: • To find the mango mealybug has a preference side of the plant that it infests • To determine the impact of various weather factors in the population fluctuation of the mango mealybug • To study the population dynamics of mango mealybug on "Chaunsa” cultivar of mango • To study the antibiosis resistance against mango mealybug on different cultivars of mango • To study the biology of mango mealybug on susceptible cultivar of mango with the objective to find out the weakest link for control measures • To find out the active time of first instar of mango mealybug during the day
42 Chapter 4 Population Dynamics, Cultivar Resistance & Biology
4.2 MATERIALS AND METHODS
4.2.1 POPULATION DYNAMICS OF MEALYBUG ON ‘CHAUNSA’ CULTIVAR OF MANGO
Two mango orchards with heavy mango mealybug ( Drosicha mangiferae Green.) infestations, in district Multan were selected at two different locations during 2005-06 and 2006-07 for the study of population dynamics. Three mango plants of ‘Chaunsa’ cultivar were taken from each orchard. Selected trees were labelled with iron sheet fixed with 2 nails written with black permanent markers as tree No-1, 2 and 3. From each tree four fruit bearing branches of 30-cm in length were selected in four different directions i.e. east, west, south and north, were tagged. The tag was written with black permanent marker as number 1, 2, 3 and 4. The abundances of pest, predators and parasites were enumerated weekly from the selected 30-cm branches including (leaves, inflorescence and branches). Average counts of insects on six trees were calculated on leaves, branches and inflorescence with respect to their directions in each year as well as cumulative average of two years. The population was also taken from the trunk of selected trees by counting the number of individuals from 900 cm 2 of bark. Weeds were assessed under the trees by identifying and counting population in a 900 cm 2 from 3 different places of ground on a weekly basis. The meteorological data were collected from Central Cotton Research Institute, Multan. Average population and abiotic factors was calculated by using Excel sheets and shown graphically. 4.2.2 POPULATION OF MANGO MEALYBUG ON DIFFERENT CULTIVARS OF MANGO
Three orchards were selected at three different locations in district Multan having the most common or popular cultivars of mango during 2005-06 and 2006-07. Among these 11 most prominent, grafted, exportable and commercial cultivars viz., ‘Chaunsa’, ‘Fajri’, ‘Langra’, ‘Black Chaunsa’, ‘Sufaid Chaunsa’, ‘Sindhri’, ‘Malda’, ‘Anwar Ratul’, ‘Dusehri’, ‘Ratul-12’, ‘Sensation’ and one seed born cultivar ‘Tukhmi’ were selected for recording the data on population of mango mealybug. There were 12 treatments and each treatment had three replications. So there were 36 plants from the 3 orchards. From each
43 Chapter 4 Population Dynamics, Cultivar Resistance & Biology plant two fruit bearing branches of 30-cm in length were selected from east and south directions. These branches were tagged. The population of the mango mealybug were counted from the selected branches on all parts i.e. leaves, inflorescence and branches fortnightly throughout the active period of pest. The data of different cultivars were compiled and analyzed through Randomized Complete Block Design on an IBM-PC Computer using M. Stat (Steel and Torrie, 1980) Package. Means were separated by Duncan’s New Multiple Range Test (DMRT) (Duncan, 1955). In the month of May, 10 egg carrying females were collected from these selected cultivars coming downward the tree via trunk having dominant similar size. The females of each cultivar were kept separately in a petri dish of 5 x 5 cm size. These were brought to the laboratory and were weighed with electronic balance, their length and width were measured with the help of steel scale. These females were returned to the orchards and were kept singly in a pit of 4 x 5 cm for egg laying which was made in semi wet soil with the help of steel spoon. The pits were covered with plastic petri dish of 5 cm and were written with black permanent marker having cultivar name and female number. At the end of June, the pits were opened and the females were taken out with steel spoon and were kept in plastic petri dishes of 5 x 5 cm size. Ovisac length and width were measured and counted the number of eggs laid. The data regarding biological parameters which were conducted in laboratory were compiled and analyzed through Completely Randomized Design.
4.2.3 METHODOLOGY TO STUDY THE BIOLOGY OF MANGO MEALYBUG UNDER FIELD CONDITIONS
Biology of mango mealybug was studied in an orchard on mango plants. The orchard was selected in District Multan. Five plants of mango cultivar ‘Chaunsa’ having age of 3-4 years and height 5-6 feet were selected. These plants were marked as 1, 2, 3, 4 and 5. After selection, the plants were cleaned before the releasing of nymph. Dried branches, leaves and small branches were removed, so that the settled nymphs can easily be observed on the plants. A funnel of 15 cm polyethylene sheet in width and length according to trunk was made on the trunk of trees by using needle, thread, solution tape and rope. The needle and thread was used on one sides of the polyethylene sheet to
44 Chapter 4 Population Dynamics, Cultivar Resistance & Biology reduce the length and can easily be wrapped on the trunk with solution tap in the form of cup. A thread of sun hemp was used below the funnel on the solution tap to make it tight. The funnel was made for the releasing of 1 st instar nymph, to stop the downward and upward movement of nymph on the ground as well as for the pupation of males and collection of egg carrying females. In this funnel small amount of mud and sand mixture with ratio 1:1 were added. After every rainfall the wet mixture were replaced with dry one. 4.2.3.1 Collection of eggs Eggs of mango mealybugs were collected on 15 th of Dec. 2006 from the infested mango orchard. These were kept in the 5 polyethylene bags of 2 kg along with soil and were placed them in the orchards for hatching. The eggs were oval in shape, yellowish in colour like turnips seed. 4.2.3.2 Hatching of Eggs Hatching of eggs were checked after every 48 hours at 10 A.M. and the newly emerged nymphs were collected with hand made aspirator and destroyed, until maximum number of nymphs were obtained. The 416 nymphs were collected on 1 st Jan., 2007 with hand made aspirator. These were kept in 8 plastic petri dishes of 5 x 5 cm size for a period of 48 hours. On 03 rd Jan., 2007, at 10 A.M., these nymphs were released in the funnel of 2 experimental plants. There were 208 nymphs /plant. The nymphs started their movement upward and were settled on the plants within 48 to 72 hours after releasing. The nymphs were observed daily. Among these nymphs, when the maximum 188 nymphs were observed half in exiuvae and half out of 2 nd instar were collected for two days with camel hair brush in plastic petri dish. These were kept in plastic petri dish for 24 hours. After that the nymphs of 2 nd instar were released on 3 rd plant. The maximum 96 nymphs of 3 rd instar were collected when observed half in exiuvae and half out with camel hair brush in plastic petri dish and kept them for 24 hours. These were released on 4th plant. When the maximum number of females (n=41)which were half in the exiuvae and half out were collected and kept them in petri dishes for 24 h and then released on 5 th plants. The speed of 1 st , 2 nd & 3rd and adult females were measured after releasing in the plant funnel. The duration of survival without food of all instar was also noted. As soon as the males came down the plants for pupation, they were counted and fifteen males
45 Chapter 4 Population Dynamics, Cultivar Resistance & Biology were picked from the plastic funnel and put them in a pit of 5 x 5 cm (width and depth). When the fuzz was secreted, the fuzz (cottony material like scretions) was removed once, twice and thrice time and adult males were observed for any effects caused by removing the fuzz. The pupation period, adult life and male copulation time was also noted. The number of eggs laid by the females were counted daily each of 5 females separately.
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4.3 RESULTS AND DISCUSSION
4.3.1 POPULATION OF MANGO MEALYBUG VERSUS PLANT SIDES The population of mango mealybug was recorded from the four cardinal points of the tree mango cultivar ‘Chaunsa’ during 2005-06 and 2006-07. The results are presented under the following sub-heading. 4.3.1.1 Population of Mango Mealybug on Leaves on Various Plant Sides
The results presented in Fig. 1 and column A of Table 1 show that the south side of the plant had significantly the highest abundance of mango mealybugs on leaves during both the study years as well as on an average basis followed by east and west sides. The north side of the mango plant showed significantly the lowest population of mango mealybug during both the study years.
2005-06 2006-07 Average
35 30 25 20 15 10
Mealybug/leaves 5 0 EAST WEST SOUTH NORTH Plant Directions
Fig 1. POPULATION OF MANGO MEALYBUG ON LEAVES PER 30- CM BRANCH LENGTH OF MANGO CULTIVAR ‘CHAUNSA’ AT VARIOUS SIDES DURING 2005-06 AND 2006-07.
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TABLE 1. POPULATION OF MANGO MEALYBUG ON CULTIVAR CHAUNSA ON VARIOUS PLANT PARTS DURING 2005-06 AND 2006-07
Sides Leaves (**) Mean (**) Inflorescence (**) Mean (**) Branch (**) Mean (**) LSD=2.62 LSD=0.94 LSD=0.49 LSD =0.34 2005-06 2006-07 LSD=1.85 2005-06 2006-07 LSD =0.66 2005-06 2006-07 East A B C 24.26 b 9.84 c 17.50 b 8.93 b 4.65 d 6.79 b 20.70 a 0.50 c 10.60 a
West 23.97 b 8.18 cd 16.07 b 10.24 a 7.15 c 8.69 a 1.84 b 0.73 c 1.29 b
South 30.89 a 10.41 c 20.64 a 10.65 a 5.44 d 8.05 a 1.84 b 0.50 c 1.70 b
North 5.88 d 2.97 e 4.43 c 3.19 e 2.26 e 2.73 c 1.76 b 0.35 c 1.05 b
F-value 37.35 132.68 17.75 148.87 1703.58 1694.77
Mean (ns) 21.25 7.85 8.25 4.87 6.54 0.52
D.F of sites=3 year =1 sites x year=3 Means sharing similar letters are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
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4.3.1.2 Mango Mealybug on Inflorescence The results shown in Fig.2 and column B of Table 1 reveal that the south and west sides of the mango plants were the most favourable during, 2005-2006. The highest population of mango mealybug was observed to be 10.65 on south side followed by west (10.24) and east (8.93) sides. The north side of the plant had significantly the lowest population of mango mealybug during, 2006-2007 (2.26) while west side of the plant showed maximum population of mango mealybug on inflorescence (7.15) followed by south (5.44) and east (4.65) sides. The north side also showed the lowest population (3.19) of mango mealybug during 2005-06. On an average of two year’s data it was observed that west side of the plant had significantly maximum population of mango mealybug followed by south (8.05) and east (6.79) sides. North side showed significantly the lowest population of mango mealybug on inflorescence i.e. 2.73 per inflorescence.
2005-06 2006-07 Average
12 10 8 6 4 2
Mealybug/infloresence 0 EAST WEST SOUTH NORTH Plant Directions
Fig 2. POPULATION OF MANGO MEALYBUG ON INFLORECENCE OF MANGO CULTIVAR ‘CHAUNSA’ AT VARIOUS SIDES DURING 2005-06 AND 2006-07.
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4.3.1.3 Mango Mealybug on Branches The results depicted in Fig. 3 and Column C of Table 1 reveal that during 2005- 2006, east side showed significantly maximum population of mango mealybug i.e. 20.7 per 30-cm branch followed by west and south sides each showing 1.8 individuals per 30 cm branch. The north side of the plant had significantly the lowest population i.e., 1.8 per 30-cm branch of mango mealybug. The results of the 2006-2007 season showed that the west side of the plants had maximum population of mango mealybug, whereas minimum on north side of the plant. East and south sides showed similar population of mango mealybug and had intermediate trend. On an average of two years data, it was observed that east side of the plant had maximum population of mango mealybug 10.6 per 30-cm on branches and differed significantly from other sides. The minimum population of mango mealybug was observed on north side of the plant i.e., 1.1 per 30- cm and did not show significant variation with those of observed on south (1.7 per 30- cm) and west (1.3 per 30-cm) sides of plant.
2005-06 2006-07 Average
2.5
2
1.5
1
0.5 Mealybug/branch 0 EAST WEST SOUTH NORTH Plant Directions
Fig 3. POPULATION OF MANGO MEALYBUG ON BRANCH OF MANGO CULTIVAR ‘CHAUNSA’ AT VARIOUS SIDES DURING 2005-06 AND 2006-07.
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4.3.1.4 Population of Mango Mealybug on Trunk and Weeds The results presented in Fig. 4 reveal that the population of mango mealybug was maximum on trunk of the tree during both the study years. However, this population was higher during 2005-2006 as compared to 2006-2007. The population of mango mealybug was observed to be the minimum on weeds. During 2005-2006, this population was higher as compared to during 2006-2007 on weeds .
2005-06 2006-07
160 140 120 100 80
weeds 60 40 20 0 No. of mealybug on trunks andontrunksmealybug of No. Trunk Weeds
Fig 4. POPULATION OF MANGO MEALYBUG ON TRUNK AND WEEDS PER 900 CM 2.
4.3.1.5 Predation Parasitization and Fungal Attacked Population of Mango Mealybug.
The mango mealybug predated by the predator, parasitized and fungal attacked specimens were observed from various sides of the plant of ‘Chaunsa’ cultivar during both the study years. The results are shown in Fig. 5. It is evident from the results that more mango mealybugs were predated during 2005-2006 than during 2006-2007. A similar trend was also observed in parasitization data i.e. higher individuals scales were parasitized during 2005-2006 than during 2006-2007. As regard to fungal attacked specimens it was observed that more fungal attacked specimens were observed during 2006-2007 than during 2005-2006.
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2005-06 2006-07
2.5
2
1.5
1
0.5 fungal pathogens
0
No.of predators, parasites and Predation Parasitized Fungal Attacked
Fig 5. POPULATION OF PREDATORS, PARASITES AND FUNGUS ATTACKED NYMPHS PER 30 CM BRANCH AND 900 CM 2 ON TRUNK OF MANGO CULTIVAR ‘CHAUNSA’ DURING 2005-06 AND 2006-07.
4.3.2 GRAPHICAL INTERACTION BETWEEN WEATHER FACTORS AND POPULATION OF MANGO MEALYBUG DURING 2005- 2006 and 2006-2007. The population of mango mealybug observed on leaves, inflorescence and branches of mango cultivar ‘Chaunsa’ and weather factors was depicted graphically in Fig. 6, 7 and 8. The objective of the study was to find the trend in population fluctuation of mango mealybug at various dates of observation corresponding to the respective weather factors of 2005-2006, 2006-2007 and on average basis. 4.3.2.1 Population of Mango Mealybug versus Weather Factors during 2005-2006 The results presented in Fig. 6 regarding population of mango mealybug versus weather factors during 2006-2007 showed that the population of mango mealybug appeared on 18 Jan. 06 with 0.1 individual per 30 cm branch and this population increased consequently on the subsequent dates of observation and reached to a peak of 34.4 individuals per 30 cm branch on 22 Feb. 06 with maximum temperature of 26.1 ºC, minimum temperature of 16.1ºC and average relative humidity of 77.9 percent. The
52 Chapter 4 Population Dynamics, Cultivar Resistance & Biology decreasing trend in this population was observed thereafter on the subsequent dates of observation and reached to a minimum of 0.1 on 31 May, 06.
2005-06 Av.pop 2005-06 TEMP.MAX 2005-06 TEMP.MINI 2005-06 AVER.RH% 2005-06 RAINFALL mm
90 40
80 35
70 30
60 25
50 20 40 Weather data Weather 15 Population Av. 30
10 20
10 5
0 0 04.1.06 11.1.06 17.1.06 25.1.06 07.12.05 14.12.05 21.12.05 28.12.05 01.02.06 08.02.06 15.02.06 22.02.06 01.03.06 08.03.06 15.03.06 22.03.06 29.03.06 05.04.06 12.04.06 19.04.06 26.04.06 03.05.06 10.05.06 17.05.06 24.05.06 31.05.06
Dates of Observation
Fig 6. POPULATION DYNAMIC AND WEATHER FACTORS DURING THE YEAR 2005-2006 ON ‘CHAUNSA’ CULTIVAR
4.3.2.2 Population of Mango Mealybug versus Weather Factors during 2006-2007 The results presented in Fig.7 regarding population of mango mealybug per 30 cm branch versus weather factors during 2006-2007 reveal that the population of mealybug was appeared on 18 Jan. 2007 and increasing trend was observed thereafter. The population reached to its highest peak on 8 Feb. 2007 i.e. 22.0 per 30 cm branch and suddenly decreased down to 5.9 per 30 cm branch on 16 Feb. 2007. The increasing trend was again observed consequently on the subsequent dates of observation and reached to the second peak on 15 Mar. 2007 with 11.70 individuals per 30 cm branch. The
53 Chapter 4 Population Dynamics, Cultivar Resistance & Biology population again in decreasing trends thereafter up to the remaining dates of observation and reached to a minimum level of 0.1 individual per 30 cm branch on 31 May, 2007. From these results it was observed that maximum temperature of 23.5 ºC, minimum temperature of 11.5 ºC, and 80 percent RH were the most favourable for the development of mango mealybug during 2006-2007.
Av.pop TEMP.MAX TEMP.MINI AVER.RH% RAINFALL mm
90 25
80
20 70
60 15 50
40 Weather factors Weather 10 Av. Population Av. 30
20 5
10
0 0 04.1.07 11.1.07 18.1.07 25.1.07 07.12.06 14.12.06 21.12.06 28.12.06 01.02.07 08.02.07 16.02.07 22.02.07 01.03.07 08.03.07 15.03.07 22.03.07 29.03.07 05.04.07 12.04.07 19.04.07 26.04.07 03.05.07 10.05.07 17.05.07 24.05.07 31.05.07 Dates of Observation
Fig 7. POPULATION DYNAMIC AND WEATHER FACTORS DURING THE YEAR 2006-2007 ON ‘CHAUNSA’ CULTIVAR
4.3.2.3 Population of Mango Mealybug versus Weather Factors on an Average Basis of Both Years Data. The results regarding average population size of mango mealybug recorded from 30-cm branch, from leaves and inflorescence during 2005-2006 and 2006-2007 versus weather factors are shown in Fig. 8. It is clear from the graph that the population appeared on Jan. 4 i.e. 0.01 individuals per 30-cm branch and increased up to the highest peak i.e. 26.6 individuals on Feb. 8. This population was decreased up to 19.8 individuals per 30 cm branch on Feb. 15. The second peak was observed i.e. 21.1 individuals per 30
54 Chapter 4 Population Dynamics, Cultivar Resistance & Biology cm branch on Feb. 22. A decreasing trend was again observed and the population reached down up to 17.2 individuals per 30 cm branch on Mar. 01. A third peak was again observed on Mar. 08 with 19.1 individual of mealybug. The decreasing trend was observed thereafter on the subsequent dates of observation with 0.1 individual of mealybug on May 31. The maximum temperature 24.1 ºC, minimum temperature 10.9 ºC, RH 79.4 percent and rainfall 0.3 mm was observed at the highest peak i.e. 26.6 individuals per 30 cm branch on Feb. 8 and these conditions were found suitable for the development of the pest.
Av.pop TEMP.MAX TEMP.MINI AVER.RH% RAINFALL mm
90 30
80 25 70
60 20
50 15 40 Weather data Weather Av. Population Av.
30 10
20 5 10
0 0 Jan,04 Jan,11 Jan,17 Jan,25 Feb,01 Feb,08 Feb,15 Feb,22 Dec,07 Dec,21 May,03 Dec,14 Dec,28 May,10 May,17 May,24 May,31 Marc,01 Marc,08 Marc,15 Marc,22 Marc,29 April,,05 April,12 April,19 April,26 Dates of Observation
Fig 8. POPULATION DYNAMIC AND WEATHER FACTORS ON ‘CHAUNSA’ CULTIVAR COMMULATIVE FROM 2005 TO 2007
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4.3.3 ROLE OF WEATHER IN POPULATION FLUCTUATION OF MANGO MEALYBUG
A study was conducted to determine the role of weather in population fluctuation of mango mealybug. The data were processed for simple correlation and Multiple Linear Regression Models with the objective to find the impact of these factors on the population fluctuation of the pest. The results are described under the following sub- sections. 4.3.3.1 Simple Correlation Between Weather Factors and Population of Mango Mealybug The results presented in Table 2 show that none of the weather factor resulted in significant effect on the population of mango mealybug during both the study years separately as well as on cumulative basis. However, the response of maximum temperature was negative whereas minimum temperature, relative humidity and rainfall exerted positive correlation values during both the study years individually as well as on cumulative basis. Table 2. EFFECT OF WEATHER FACTORS ON THE POPULATION FLUCTUATION OF MANGO MEALYBUG DURING THE STUDY YEARS 2005-2006 AND 2006-2007.
r-values Weather Factors Years Temperature oC R.H. (%) R.F. (mm) Maximum Minimum 2005-06 -0.009 0.182 0.144 0.157 2006-07 -0.165 0.097 0.266 0.101 Cumulative -0.095 0.151 0.170 0.051
4.3.3.2 Multiple Linear Regression Models The results relating to Multiple Linear Regression Models along with coefficient of determination values between weather factors and population of mango mealybug during 2005-2006, 2006-2007 and on cumulative basis are given in Table 3. It is evident from the results that during 2005-2006, maximum temperature did not show any impact on the population fluctuation of mango mealybug. The effect of maximum and minimum
56 Chapter 4 Population Dynamics, Cultivar Resistance & Biology temperature showed significant impact when computed together and contributed 21.5 percent role in the population fluctuation of the pest. The role was increased up to 27.4 percent in population fluctuation of the pest when the effect of maximum temperature, minimum temperature and RH was computed together. Rainfall did not show any impact on the population fluctuation of the pest. Table 3. MULTIPLE LINEAR REGRESSION MODELS BETWEEN POPULATION OF MANGO MEALYBUG AND WEATHER FACTORS.
Years Regression Equation D.F. F- P- R2 Individual value value Role (%) 2005-06 Y = 2.8032 – 0.0233 X1 24 0.00 0.97 0.00 0.00 Y = 9.6369 – 2.6986 X1* + 1.9752 ** 23 3.59 0.62 0.22 21.50 X2 Y = -3.9438 – 1.4058 X1 + 1.8798 X2* 22 2.12 0.08 0.27 5.90 + 0.8781 X3 Y = -3.8621 – 1.4272 X1 + 1.8934 X2* 21 2.98 0.09 0.27 0.00 + 0.8803 X3 – 0.0412 X4 2006-07 Y = 2.2962 – 0.0625 X1 24 2.01 0.93 0.03 2.7 Y = 1.8111 – 0.0667 X1 + 0.1357 X2 23 2.41 0.75 0.04 1.3 **Y -13.6903–0.0803X1 + 1.4100X2** 22 4.60 0.01 0.48 44.3 = + 1.338 X3** **Y -15.7025–0.1194X1+ 1.5534 X2** 21 4.95 0.01 0.55 6.4 = + 1.6068 X3** - 0.3814 X4 2005-06 + 2006-07 Y = 2.7087 – 0.0724 X1 50 2.16 0.32 0.01 0.9 Y = 1.7959 – 0.1050 X1 + 0.2902 X2 49 3.97 0.26 0.04 3.2 **Y -12.5385–0.1014 X1 + 1.3794 48 7.39 0.00 0.29 24.7 = X2** + 1.2707 X3** **Y= -13.4251–0.1307 X1 + 1.4598 47 5.79 0.00 0.31 1.9 X2** + 1.4078 X3 ** - 0.3361 X4 Where X1= Max. Temperature X2= Mini. Temperature X3= R.H percent X4=Rainfall R2 = Coefficient of Determination * = Significant at P < 0.05. ** Significant at P < 0.01.
During 2006-2007, maximum temperature contributed 2.7 percent role in population fluctuation of the pest with nonsignificant impact. The role of maximum and minimum temperature reached up to 4 percent when the effect of both parameters was computed together. The combination of maximum temperature, minimum temperature
57 Chapter 4 Population Dynamics, Cultivar Resistance & Biology and relative humidity showed significant impact on the population fluctuation of the pest and contributed 48.3 percent role. Similarly, the effect of all the weather factors exerted 54.7 percent role in population fluctuation of mango mealybug when the effect of these factors was computed together. In this equation minimum temperature and relative humidity showed significant impact with positive response, whereas rainfall and maximum temperature played nonsignificant impact with negative response. From these results it was observed that relative humidity was the most important factor which contributed maximum role in population fluctuation of the pest i.e. 44.3 percent. On cumulative basis, maximum temperature again showed nonsignificant impact with minimum contribution i.e. 0.9 percent in population fluctuation of the pest. The impact was reached up to 4.1 percent when the effect of maximum temperature and minimum temperature was computed together. Relative humidity again proved to be the most important factor which alone contributed 24.7 percent role in population fluctuation of the pest when the effect of maximum and minimum temperatures were computed with relative humidity. Rain fall did not show significant role in population fluctuation of the pest and contributed only 1.9 percent role . 4.3.4 ACTIVE PERIOD OF NYMPHS MOVING UP THE TREES AT VARIOUS DAY TIMES The study was conducted to observe the activity of mango mealybug at various intervals of the day viz. 8, 10, 12, 14, 16 and 18 hours. It is evident from the results in Table 4 that maximum activity of the pest was observed at 12 noon on all the dates of observation. The population was decreased tremendously at 14 hours followed by 16 and 18 hours. From these results it was concluded that 12 noon is the most favourable time for maximum activity of the pest.
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Table 4. ACTIVATION TIME OF MANGO MEALYBUG NYMPHS DURING THE DAY.
12.00 1400 1600 1800 Dated 8.00AM 10.00AM Noon hours hours hours 01.02.06 7 43 72 32 12 3 02.02.06 6 36 63 42 19 4 03.02.06 9 41 67 51 21 2 04.02.06 7 35 58 34 14 3 05.02.06 9 39 62 35 11 5 06.02.06 8 32 43 22 13 2 07.02.06 7 41 29 19 8 3 08.02.06 8 55 22 11 5 4 09.02.06 4 43 17 5 3 1 10.02.06 3 4 9 4 1 1 11.02.06 1 2 7 3 0 0 12.02.06 0 1 3 2 0 1
4.3.5 POPULATION OF MANGO MEALYBUG ON DIFFERENT CULTIVARS OF MANGO The study was conducted to determine the response of various cultivars of mango viz., ‘Chaunsa’, ‘Fajri’, ‘Langra’, ‘Black Chaunsa’, ‘Sufaid Chaunsa’, ‘Sindhri’, ‘Malda’, ‘Dusehri’, ‘Anwar Ratul’, ‘Ratul-12’, ‘Tukhmi’ and ‘Sensation’ for relative resistance/susceptibility against mango mealybug during 2005-2006 and 2006-2007. The results are presented under the following sub-sections. 4.3.5.1 Population of Mango Mealybug During 2005-2006 The means comparison of data regarding population of mango mealybug per branch (30-cm in length) on East and South sides in different cultivars of mango at various dates are shown in Table 5a and 5b. Significant variations (P < 0.01) were found to exist among dates of observation, different cultivars, between plant directions and in their interactions.
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4.3.5.1.1 Cultivar Resistance The means were compared by DMR Test at P = 0.05 and the results are given in Table 5a. It is clear from the results that the maximum mealybug (104.9/branch) was observed on cultivar ‘Chaunsa’ and differed significantly from those of recorded on all other cultivars of mango. The minimum individuals of mango mealybug was observed on ‘Tukhmi’ (18.3/branch) and also differed significantly from those of recorded on all other cultivars. The cultivars ‘Sensation’ and ‘Sindhri’ did not show significant difference with each other having 51.7 and 51.8 mealybugs per branch, respectively. All the other cultivars of mango showed significant difference with one another. The position of cultivars in descending order was as under: ‘Chaunsa’ > ‘Black Chaunsa’ > ‘Malda’ > ‘Fajri’ > ‘Ratul-12’ > ‘Langra’ > ‘Sindhri’ > ‘Sensation’ > ‘Dusehri’ > ‘Sufaid Chaunsa’ > ‘Anwar Ratul’ > ‘Tukhmi’. Table 5a. MEANS COMPARISON OF THE DATA REGARDING POPULATION OF MANGO MEALYBUG ON DIFFERENT CULTIVARS OF MANGO AT VARIOUS PLANT SIDES DURING 2005-06.
Direction x varieties (**) LSD = 1.11 Average(**) Name of Cultivar East South LSD = 0.78 Anwar Ratul 14.47 s 26.60 p 20.53 j Black Chaunsa 78.70 e 103.80 b 91.25 b Chaunsa 89.70 d 120.10 a 104.90 a Dusehri 26.23 p 49.80 k 38.02 h Fajri 71.20 h 89.77 d 80.48 d Langra 44.77 l 74.27 f 59.52 f Malda 73.00 g 94.93 c 83.97 c Ratul-12 61.40 j 78.13 e 69.77 e Sensation 38.63 n 64.73 i 51.68 g Sindhri 41.27 m 62.40 j 51.83 g Sufaid Chaunsa 21.83 r 33.47 o 27.65 i Tukhmi 12.37 k 24.17 q 18.27 k Average 47.80 b 68.51 a F-value 137.8 10235.46 Cultivar (n=12) cardinal direction (n=2) DF= 11 Means sharing similar letters are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
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4.3.5.1.2 Plant Direction The south side of the plant had significantly higher population of mango mealybug i.e. 68.51 individuals per branch whereas 47.80 individuals per branch than the east side (Table 5a). Based on interactional response between sides and cultivars, it was observed that the maximum population of mango mealybug was observed at South side on ‘Chaunsa’ (120.10/branch), whereas the similar trend was also recorded on the same cultivar on East side (89.70/branch). Tukhmi showed minimum population on both the sides i.e. 12.37 and 24.17 per branch, respectively. In general the populations of mango mealybugs were lower on East side as compared to South in all the cultivars of mango. 4.3.5.1.3 Period of Abundance of Mango Mealybug. The data regarding the mango mealybug observed on various dates of observation are given in Table 5b. The maximum population of mango mealybug was recorded on Mar. 14, 2006 and differed significantly from those of recorded at all the dates of observation. The population started to appear at 4 th week of Jan. and reached to a peak on the subsequent date of observation i.e. Feb. 11, 2006 with 114. 33 per branch and this population again fluctuate to lower side on Feb. 26, 2006 i.e. 93.7 per branch. This population again increased and reached to the highest peak i.e. 130.9 on Mar. 14, 2006. Decreasing trend was observed continuously thereafter on all the subsequent dates of observation and reached to the minimum level of 1.4 per branch. Keeping in view the results regarding interactional responses, it was observed that south side showed significantly higher population of mango mealybug as compared to east side almost at all the dates of observation. The fluctuation trend on both sides was similar corresponding to the dates.
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Table 5b. MEAN COMPARISON OF THE DATA REGARDING POPULATION OF MANGO MEALYBUG ON DIFFERENT DATES AT VARIOUS PLANT SIDES DURING 2005-2006.
Dates of Observation Dates x direction(**) LSD = 1.01 Average (**) East South LSD = 0.72 11-1-2006 0.00 o 0.00 o 0.00 h 27-1-2006 0.81 no 2.08 m 1.44 g 11-2-2006 98.11 f 130.56 b 114.33 b 26-2-2006 79.36 g 108.11 e 93.74 d 14-3-2006 113.42 d 148.44 a 130.93 a 28-3-2006 74.14 h 120.14 c 97.14 c 12-4-2006 49.50 j 79.22 j 64.36 e 27-4-2006 50.72 i 78.86 j 64.79 e 10-5-2006 10.94 l 15.92 k 13.43 f 25-5-2006 0.97 no 1.81 mn 1.39 g F-value 1097.0 38572.9 Dates (n=10) cardinal direction (n=2) df=9 Means sharing similar letters are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01 .
CONCLUSION: • The cultivar ‘Chaunsa’ cultivar was found to be relatively susceptible, whereas ‘Tukhmi’ the resistant. The south side of the plant showed higher population than the east. • Second week of Mar. was found to be the most favourable for the development of mango mealybug during 2006. 4.3.5.2 Population of Mango Mealybug During 2006-2007 The mean comparison of data regarding population of mango mealybug per branch of 30-cm length on east and south directions in different mango cultivars during 2007. The means were compared by DMR Test and shown in Table 6a and 6b.
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4.3.5.2.1 Cultivar Resistance The results (Table 6a) show significant variations among mango cultivars regarding population of mango mealybug per branch of 30 cm length. The cultivar ‘Chaunsa’ again found to be comparatively susceptible showing maximum population of mango mealybug i.e. 69.8 per branch, whereas ‘Tukhmi’ showed minimum population of mango mealybug i.e. 13.5 per branch which showed similar response statistically with those of ‘Anwar Ratul’ with 14.2 individuals per branch of the pest. The descending order of the cultivars based on population of mango mealybug towards susceptibility was as follows: ‘Chaunsa’ > ‘Black Chaunsa’ > ‘Malda’ > ‘Fajri’ > ‘Ratul-12’ > ‘Langra’ > ‘Sensation’ > ‘Sindhri’ > ‘Dusehri’ > ‘Sufaid Chaunsa’ > ‘Anwar Ratul’ and ‘Tukhmi’. 4.3.5.2.2 Plant Direction The data presented in Table 6a reveal significant difference between sides regarding population of mango mealybug. The South side of the plant showed significantly the highest populations of mango mealybug i.e. 51.5 per branch, whereas east side showed the lowest populations i.e. 33.4 per branch. Furthermore, all the cultivars of mango possessed significantly higher population of mango mealybug on south side of the plant as compared to east. The trend of cultivars towards susceptibility/resistance was the same as those of observed in their mean values. 4.3.5.2.3 Period of Abundance The results presented in Table 6b showed significant difference among various dates of observation and between interaction of dates of observation and plant sides. The population of mango mealybug started to appear on Jan. 26, 2007 i.e. 2.9 per branch of 30-cm length. This population tremendously jumped to the highest peak i.e. 94.9 individuals per branch on the subsequent dates of observation i.e. Feb. 13, 2007. This population decreased down to 79.5 per branch on Feb. 28, 2007 and then it increased to 86.7 individuals per branch on Mar. 14, 2007. The decreasing trend in population of mango mealybug was observed thereafter on the subsequent dates of observation and reached to 3.5 per branch on May 25, 2007. Similar trend was observed in the interaction between dates of observation and plant sides. Furthermore, south side showed
63 Chapter 4 Population Dynamics, Cultivar Resistance & Biology significantly higher population of mango mealybug as compared to east side at all the dates of observation. Table 6a. MEANS COMPARISON OF THE DATA REGARDING POPULATION OF MANGO MEALYBUG ON DIFFERENT CULTIVARS OF MANGO AT VARIOUS PLANT SIDES DURING 2006-2007.
Varieties x direction(**) LSD = 1.06 Average (**) Name of Cultivar East South LSD = 0.75 Anwar Ratul 12.20 t 16.20 s 14.20 k Black Chaunsa 51.47 h 80.40 b 65.93 b Chaunsa 54.37 g 85.30 a 69.83 a Dusehri 21.00 r 30.90 o 25.95 i Fajri 47.17 j 71.80 d 59.48 d Langra 36.73 m 56.13 f 46.43 f Malda 48.90 i 74.90 c 61.90 c Ratul-12 39.83 l 63.60 e 51.72 e Sensation 34.57 n 56.27 f 45.42 g Sindhri 26.97 p 43.17 k 35.07 h Sufaid Chaunsa 16.57 s 23.20 q 19.88 j Tukhmi 10.50 u 16.40 s 13.45 k Average 33.36 b 51.52 a F-value 307.5 5695.6 Cultivar (n=12) cardinal direction (n=2) df=11 Means sharing similar letters are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
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Table 6b. MEAN COMPARISON OF THE DATA REGARDING POPULATION OF MANGO MEALYBUG ON DIFFERENT DATES OF OBSERVATION AT VARIOUS PLANT SIDES DURING 2006-2007.
Dates of Dates x direction (**) LSD = 0.97 Average(**) Observation East South LSD = 0.68 11-1-2007 0.00 r 0.00 r 0.00 h 26-1-2007 2.28 q 3.53 p 2.90 g 13-2-2007 77.50 e 112.22 a 94.86 a 28-2-2007 64.11 g 94.81 c 79.46 c 14-3-2007 70.39 f 102.92 b 86.65 b 28-3-2007 49.19 h 87.00 d 68.10 d 12-4-2007 27.58 l 37.17 j 32.38 e 27-4-2007 24.22 m 41.89 i 33.06 e 10-5-2007 15.97 n 31.00 k 23.49 f 25-5-2007 2.31 q 4.69 o 3.50 g F-value 903.9 22300.0 Dates (n=10) cardinal direction (n=2) df=9 F-value= Means sharing similar letters are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference value. * = Significant at P < 0.05. ** = Significant at P < 0.01. Conclusion: The cultivar ‘Chaunsa’ was found to be relatively susceptible followed by ‘Black ‘Chaunsa’ and ‘Malda’, whereas ‘Tukhmi’ and ‘Anwar Ratul’ were comparatively resistant with minimum population of mango mealybug. South direction of the plant showed comparatively higher population of mango mealybug as compared to east direction in all the cultivars of mango as well as on average basis. Second week of Feb. and Mar. showed highest population of mango mealybug. In general, the 2 nd week of Feb. to 4 th week of Mar. was the most favorable period for the development of mango mealybug.
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4.3.5.3 Population of Mango Mealybug on Cumulative Basis of Both Years Studies The data regarding mango mealybug on different cultivars of mango at various dates of observation during both the study years are presented Table 7a. The results reveal that all the parameters such as years, dates of observation, plant directions and cultivars showed significant difference individually as well as on their all possible interactions. The results are described as under. The results presented in Table 7a reveal that the cultivar ‘Chaunsa’ was found susceptible to mango mealybug showing maximum population of the pest i.e. 87.4 per 30-cm branch and differed significantly from those of observed in all other cultivars. The cultivar ‘Tukhmi’ was found comparatively resistant to mango mealybug with minimum population of the pest i.e. 15.9 per 30-cm branch. Furthermore, all the cultivars differed significantly with one another. The descending position of these cultivars are as under. ‘Chaunsa’ > ‘Black Chaunsa’ > ‘Malda’ > ‘Fajri’ > ‘Ratul-12’ > ‘Langra’ > ‘Sensation’ > ‘Sindhri’ > ‘Dusehri’ > ‘Sufaid Chaunsa’ > ‘Anwar Ratul’ >’Tukhmi’. The south direction of the plant showed significantly higher population as compared to east direction in all the cultivars of mango. Significantly higher population of mango mealybug was recorded to be 102.7 per 30 cm branch on south side as compared to east side with 72.0 per 30 cm branch. Similar trend was observed in all the cultivars. The data presented in Table 7b based on both study years revealed that population of mango mealybug was appeared during the 4 th week of Jan. and reached to a peak during 2 nd week of Feb. This population decreased down during 4 th week of Feb. and then reached to the highest peak during 2 nd week of Mar. This population decreased down thereafter subsequently and reached to a minimum level of 2.4 per branch of 30-cm length during 4 th week of May. On the basis interaction, south side showed higher population of mango mealybug as compared to the east side at all the dates of observation. Mar. 14 th had higher population i.e. 125.7 per 30-cm branch length on south side as compared to east side with 91.9 individuals per 30-cm branch length.
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Conclusion: • The cultivar ‘Chaunsa’ proved to be a susceptible, whereas ‘Tukhmi’ was a resistant to mango mealybug. • Maximum population of mealybug was recorded on the South direction of the plants. • The months of Feb. and Mar. were the most favourable period for the development of the pest. Table 7a. MEAN COMPARISON OF THE DATA REGARDING POPULATION OF MANGO MEALYBUG ON DIFFERENT CULTIVARS OF MANGO AT VARIOUS PLANT SIDES (AVERAGE OF BOTH YEARS).
Varieties x direction (**) LSD = 0.77 Average (**) Name of Cultivars East South LSD = 0.54 Chaunsa 72.03 e 102.70 a 87.38 a Fajri 59.18 i 80.78 d 69.98 d Langra 40.75 l 65.20 g 52.97 f Black Chaunsa 65.08 g 92.10 b 78.59 b Sufaid Chaunsa 19.20 s 28.33 o 23.77 j Sindhri 34.12 n 52.78 j 43.45 h Malda 60.95 h 84.92 c 72.93 c Dusehri 23.62 p 40.35 l 31.98 i Anwar Ratul 13.33 t 21.40 q 17.37 k Ratul-12 50.62 k 70.87 f 60.74 e Tukhmi 11.43 u 20.28 r 15.86 l Sensation 36.60 m 60.50 h 48.55 g F-value 362.0 15546.2 Cultivar (n=12) cardinal direction (n=2) df= 11 Means sharing similar letters are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
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Table 7b. MEAN COMPARISON OF THE DATA REGARDING POPULATION OF MANGO MEALYBUG ON DIFFERENT DATES OF OBSERVATION AT VARIOUS PLANT SIDES (AVERAGE OF BOTH YEARS).
Dates of Dates x direction (**) LSD = 0.70 Average(**) Observation East South LSD = 0.50 January 11 0.00 q 0.00 q 0.00 i January 26 1.54 p 2.81 o 2.17 h February13 87.81 f 121.39 b 104.60 b February 28 71.74 g 101.46 d 86.60 c March 14 91.90 e 125.68 a 108.79 a March 28 61.67 h 103.57 c 82.62 d April 12 38.54 k 58.19 j 48.37 f April 27 37.47 l 60.38 i 48.92 e May 10 13.46 n 23.46 m 18.46 g May 25 1.64 p 3.25 o 2.44 h F-value 1865.0 58781.0 Dates (n=10) cardinal direction (n=2) df=9 Means sharing similar letters are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
4.3.6 ANTIBIOSIS RESISTANCE AGAINST MANGO MEALYBUG IN DIFFERENT CULTIVARS OF MANGO Various biological parameters viz., number of eggs laid per female, weight of female, length and width of female, length and width of ovisac on different cultivars of mango were studied during 2007 under field conditions. The results are shown in Table 8, Column A to F and described under the following sub-sections. 4.3.6.1 Number of Eggs Laid Per Female The comparison of data regarding mean numbers of eggs laid per female are given in Table 8. The results reveal highly significant difference among genotypes. The means were compared by DMR Test at P = 0.05. It is evident from the results (Table 8, Column A) that maximum number of eggs were laid on the cultivar ‘Chaunsa’
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(335.9/female) and did not differ significantly from those of collected from ‘Black ‘Chaunsa’ (328.9/female) and followed by 305.6, 302.5, 301.9, 293.5 and 286.7 number of eggs laid by a single female on ‘Malda’, ‘Fajri’, ‘Langra’, ‘Ratul-12’ and ‘Sensation’, respectively. The later mentioned figures did not show significant difference with one another. The minimum number of eggs laid by a single female of mango mealybug was 156.0 on ‘Anwar Ratul’ and did not show significant difference with 159.8 eggs per female on ‘Tukhmi’. The cultivars ‘Sufaid Chaunsa’ and ‘Dusehri’ possessed 187.2 and 186.6 number of eggs per female, respectively and did not show significant differences. The number of eggs laid by a single female was 217.0 on Sindhri and showed significant variations with those of found on all other cultivars of mango. 4.3.6.2 Weight of Female The results (Table 8, Column B) show significant difference among mango cultivars regarding weight of female. The specimens of mealybug collected from ‘Chaunsa’ cultivar had maximum weight i.e. 0.24 g/female and did not show significant difference with 0.23 g/female for those specimens which were collected from the cultivar ‘Black Chaunsa’ followed by 0.22 and 0.22 g/female on ‘Malda’ and ‘Fajri’, respectively and did not show significant difference with one another. The cultivars ‘Sensation’, ‘Ratul-12’ and ‘Langra’ showed similar response statistically regarding weight of female i.e. 0.19, 0.19 and 0.18 g/female, respectively. The female collected from ‘Sindhri’ showed 0.17 g/weight per female and differed significantly from those of observed on all other cultivars of mango. The minimum weight of female was observed on those specimens that were collected from ‘Tukhmi’ cultivar i.e. 0.11 g/female and did not show significant difference with those of recorded on ‘Anwar Ratul’ i.e. 0.12 g/female. Similar trend was observed in between ‘Dusehri’ and ‘Anwar Ratul’ which showed 0.12 and 0.12 g weight/female, respectively. 4.3.6.3 Length of Female The results regarding length of female of mango mealybug on different cultivars of mango are shown in Table 8, Column C. The results reveal significant variations among cultivars. The maximum length of female was observed on ‘Chaunsa’ i.e. 1.6 cm/female and showed significant difference from those of observed on all other cultivars
69 Chapter 4 Population Dynamics, Cultivar Resistance & Biology followed by 1.5, 1.5, 1.5, 1.5, 1.5 and 1.5 cm/female on ‘Malda’, ‘Black ‘Chaunsa’, ‘Ratul-12’, ‘Sensation’, ‘Langra’ and ‘Fajri’, respectively and the later mentioned figures were not significantly different from one another.The minimum length of female was observed on cultivar ‘Tukhmi’ and ‘Sindhri’ each showing 1.2 cm/female and did not show significant variation with 1.2 cm/female on ‘Anwar Ratul’. The average length of female was found to be 1.3 cm per female on ‘Sufaid Chaunsa’ and showed nonsignificant difference with 1.28 cm per female on ‘Dusehri’. Table 8. MEANS COMPARISON OF THE DATA REGARDING BIOLOGICAL PARAMETERS OF MANGO MEALYBUG FEEDING ON DIFFERENT CULTIVARS OF MANGO UNDER FIELD CONDITION. Eggs Female Female Female Ovisac Ovisac Name of per Weight Length Width length width Cultivars female (g) (cm) (cm) (mm) (mm) (A)** (B)** (C)** (D)** (E) ** (F)** Anwar Ratul 156.00 e 0.116 fg 1.22 d 0.51 f 5.90 b 4.90 b Black Chaunsa 328.90 a 0.231 a 1.53 b 0.74 ab 10.20 a 6.20 a Chaunsa 335.90 a 0.239 a 1.63 a 0.80 a 10.10 a 6.10 a Dusehri 186.60 d 0.121 ef 1.28 b 0.50 f 5.90 b 4.70 b Fajri 302.50 b 0.219 b 1.50 b 0.68 bcd 9.90 a 5.80 a Langra 301.90 b 0.183 c 1.51 b 0.69 bc 10.10 a 6.00 a Malda 305.60 b 0.222 b 1.54 d 0.70 b 10.00 a 6.30 a Ratul-12 293.50 b 0.186 c 1.52 b 0.61 e 9.80 a 6.10 a Sensation 286.70 b 0.186 c 1.52 b 0.63 cde 9.60 a 5.80 a Sindhri 217.00 c 0.167 d 1.21 cd 0.62 de 5.80 b 5.00 b Sufaid Chaunsa 187.20 d 0.126 e 1.34 c 0.51 f 5.80 b 4.90 b Tukhmi 159.80 e 0.113 g 1.21 d 0.45 f 6.00 b 4.70 b LSD at 5% 18.26076 0.00772 0.07201 0.06429 0.7495 0.7168 F-value 109.5 292.0 35.3 22.4 62.0 6.3 Cultivars (n=12) biological parameters (n=6) df=11 Means sharing similar letters in column A to F are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
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4.3.6.4 Width of Female The data relating to the width of female in different cultivars of mango and their means comparison are presented in Table 8, Column D, reveal significant difference among cultivars. The maximum width (0.80 cm) of female was observed on cultivar ‘Chaunsa’ which showed a susceptible response and did not differ significantly from 0.74 cm width of female on ‘Black Chaunsa’. The later mention figure also showed nonsignificant variation with those of observed on ‘Fajri’, ‘Langra’ and ‘Malda’ with 0.68, 0.69 and 0.70 cm width of female, respectively. The minimum width of female was recorded to be 0.45 cm in ‘Tukhmi’ and did not show significant variation with those of observed on ‘Anwar Ratul’, ‘Sufaid Chaunsa’ and ‘Dusehri’ with 0.51, 0.51 and 0.50 cm width of female, respectively. Nonsignificant difference was found to exist between ‘Ratul-12’, ‘Sindhri’ and ‘Sensation’ which showed 0.61, 0.62 and 0.63 cm width of female, respectively. The later mentioned two figures also showed nonsignificant difference with those of observed in Fajri. 4.3.6.5 Length of Ovisac The results presented in Table 8, Column E, showed significant difference among mango cultivars regarding ovisac length of mango mealybug. The maximum length of ovisac i.e. 10.20 mm/female was found on cultivar ‘Black Chaunsa’ and did not show significant difference with those of observed on ‘Chaunsa’, ‘Langra’, ‘Malda’, ‘Fajri’, ‘Ratul-12’ and ‘Sensation’ with 10.10, 10.10, 10.00, 9.90, 9.80 and 9.60 mm length of ovisac, respectively. The minimum length of ovisac i.e. 5.80 mm each on ‘Sufaid Chaunsa’ and ‘Sindhri’ was recorded and did not show significant difference with 5.90, 5.90 and 6.00 on ‘Dusehri’, ‘Anwar Ratul’ and ‘Tukhmi’, respectively. 4.3.6.6 Width of Ovisac The results regarding width of ovisac of female mango mealybug are given in Table 8, Column F. The maximum width of ovisac was observed to be 6.3 mm on ‘Malda’ and did not differ significantly with 6.2, 6.1, 6.1, 6.0, 5.8 and 5.8 on ‘Black Chaunsa’, ‘Chaunsa’, ‘Ratul-12’, ‘Langra’, ‘Fajri’ and ‘Sensation’, respectively. The minimum width of ovisac was found on those specimens that were collected from the cultivars ‘Tukhmi’ and ‘Dusehri’ each showing 4.7 mm/female and followed by 4.9, 4.9
71 Chapter 4 Population Dynamics, Cultivar Resistance & Biology and 5.0 mm width of ovisac on ‘Anwar Ratul’, ‘Sufaid Chaunsa’ and ‘Sindhri’, respectively. 4.3.7 BIOLOGY OF MANGO MEALYBUG ON SUSCEPTIBLE CULTIVAR ‘CHAUNSA’.
4.3.7.1 First Stadium Maximum nymphs hatched on 30 th and 31 st of Dec. 2006 i.e. 416 were caught from the polyethylene bags with hand made aspirator. These were kept in plastic petri dishes at ambient temperature in the orchard for 48 hours. On 03-01-07, the nymphs were released at 10 A.M. in the plastic funnel of two plants. They started their movement upward the plants. All the nymphs settled themselves on the leaves of plants within 48-72 hours. They were checked daily. After 39 days 4 nymphs out of 405 (11 were found absent) to stopped feeding, became sluggish and attached to the leaves with no excretion. These were encircled with black permanent maker with date on the leaves. The nymphs were covered with whitish powder. After 4-5 days, a streak appeared longitudinally on the head side of the nymphs and the second instar nymph comes out but remained half in the exiuvae. After 24 hours the nymphs shed the exiuvae and again started feeding. All the nymphs shed their exiuvae within 56.5 days (Table 9, Appendix 1). The maximum number of 188 nymphs were observed which were half in the exiuvae on two dates i.e. on 21 to 22 Feb. were separated from the leaves on 25 th and 26 th Feb. with camel hair brush in petri dish. These were kept in room present in the orchard for a period of 24 hours. 4.3.7.2 Second Stadium The collected 188 nymphs were released on 28 th Feb. in the funnel of 3 rd plant in the morning at 10 A.M. These go upward and settled on the leaves and tip of branches within 48 hours. After 13 days i.e. on 10 th Mar. 2 nymphs out of 188 stop their feeding with no excretion present on the leaves, covered with whitish powder and were encircled with date. After 4 days on 13 th Mar. a streak appeared on the head side longitudinally and nymphs crawled out but remained half in exiuvae. After 24 hours on 14 th Mar. the nymphs shed exiuvae and again started their feeding. All the nymphs shed their exiuvae within 26 days (Table 9, Appendix 2). The maximum number of 96 nymphs were observed which were half in the exiuvae on 15 to 16 Mar. were separated from the leaves
72 Chapter 4 Population Dynamics, Cultivar Resistance & Biology with camel hair brush in petri dish. These were kept in room present in the orchard for a period of 24 hours. Table 9. LIFECYCLE OF MANGO MEALYBUG ON CHAUNSA MANGO ON AN AVERAGE
Stage Duration Females Males First Stadium 56.5 days 56.5 days Second Stadium 26 days 26 days Third Stadium 19.5 days 3 days Pupa Absent 12 days Adult life 29 days 6 days Number of eggs laid 282 /female - Number of days in which 12.5 days - eggs completed Total life from hatching to 143 days 103 days death of adult
4.3.7.3 Third Stadium The collected 96 nymphs were released in the funnel of 4 th plant on 17 th Mar. Among these, 1 nymph out of 96 stopped feeding on 25 th Mar. and was seen under the main branch of the plant covered with whitish powder. After 5 days, on 30 th , Mar. a streak appeared on the head side longitudinally and nymphs crawled out from the exiuvae but remained half in and half out. After 24 hours, the nymphs leaved the exiuvae and again started their feeding. All the nymphs shed their exiuvae within 19.5 days (Table 9, Appendix 3). As soon as the females shed the exiuvae mating started. A maximum numbers of 41 nymphs were observed on 28 th and 29 th Mar. stopped feeding which were collected on 3 rd Apr. when they were half in the exiuvae and separated from the leaves with camel hair brush in petri dish. These were kept at room temperature in the orchard for 24 hours. 4.3.7.4 Females Forty one females were released on 5 th plant on 4 th Apr. As soon as the females were released on 5 th plant, the males gathered there and started the mating. After mating
73 Chapter 4 Population Dynamics, Cultivar Resistance & Biology the females started feeding on the plants. All the females come down the tree within 29 days. The females took 12.5 days to lay its full quota of eggs, after which it died but its ovisac remained attached to the body. Total lifecycle of female from hatching to die was 143 days (Table 9, Appendix 4). 4.3.7.5 Males The 59 male’s nymphs were recorded from all the 5 plants started to come down on 2 nd Apr, (Appendix 5) stopped feeding, gathered in the funnel and hibernate in the material present in the funnel. After 1 to 5 days the males started pupation. But some pupate soon after emerging from the exiuvae. Ten males were picked from the funnel before pupation and put in to a pit of 1.5 x 2 inch covered with petri dish for further study. The males were checked daily, in the beginning they stopped their movement and started covering with whitish cocoon on their bodies. Pupation was completed within 2 to 3 days after keeping in the pit and remained in this condition for 12 days. After this period, winged males of crimson colour came out from the pupae. Adult male life was 6 days and male completed life cycle within 103 days (Table 9). The insect has only one generation in a year. 4.3.8 STUDY ON THE BEHAVIOUR OF THE PEST Besides the study of various aspects of the biology of mango mealybug, some behavioural factors were also taken into consideration for getting more information about the pest for the effective management and provide base line to the Entomologists. The aspects are given as under: 4.3.8.1 Speed of Nymphs The nymphs were negatively geotropic. These started their movements upward the plant with an average speed of 12.4 cm/minute is given in Appendix 6. Whereas, second instar move with a speed of an average speed of 17.3 cm / minute. The 3 rd instar nymph moves with an average speed of 37.1 cm / minute. 4.3.8.2 Removal of Whitish Cocoon Whitish fuzz (naturally occurring on pupa of males in mealybug like cottony secretions) was removed from the body of 5 males it were constructed again (after its removal) is given in Appendix 7-9, fuzz of four insects were removed 2 nd time again, it also secreted again but very small in amount, from this pupa healthy males come out.
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Again the fuzz of three insects was removed 3 rd time, they did not secrete the fuzz and dessicated, so no winged males emerged from the pupa. It was concluded that if the fuzz removed two times, healthy male comes out and if it was removed 3 rd time, the male pupa will not secrete the fuzz again and died. 4.3.8.3 Egg Laying Behaviour For counting the eggs daily laid by the females, a trench of size 3.81 x 5.08 cm was dug under the shade of tree in moist soil. In this trench, 5 females were kept singly for egg laying is given in Fig. 9 Appendix 10. These trenches were covered with plastic petri dish of size 5.08 cm and labeled them as R1, R2, R3, R4, R5 with date. After covering the trenches, mud and dried leaves were spread over the dishes for darkness. Egg were counted daily. It was observed that the first females started egg laying after 5 days and the fifth female started egg laying 12 days after keeping in trench. In the beginning, maximum eggs were laid daily i.e. 56/day and at the end minimum eggs were laid i.e. 1/day. The duration of egg laying was ranged from 221 to 361/female in 9 to 16 days. (n=5 mean eggs= 282.4 minimum eggs=221 maximum eggs= 362 SD=36.7) 4.3.8.4 Nymphs Live Without Food First instar nymph lived without food for 5 to 19 days, 2 nd & 3 rd instar lived 3 to 23 days whereas, adult females lived up to 8-17 days without feeding is given in (Appendix 11-13). 4.3.8.5 Copulation Time The males fly where the females are presents. Mating time of males vary and were ranged from 6.00 to 20.50 minute. The average mating time per female was 11.57/ minute is given in (Fig 9 Appendix 14). (n=20 mean mating time= 12.2 minute/male minimum= 6.0 maximum= 20.5 SD=5.1)
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350
300
250
200
150
100
50
0 Av. No of eggs laid Av. Mating time
Fig 9. AVERAGE NUMBER OF EGGS LAID PER FEMALE AND AVERAGE MATING TIME WITH STANDARD DEVIATION
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4.4 DISCUSSION
Population fluctuations of mango mealybug on twelve cultivars viz., ‘Chaunsa’, ‘Fajri’, ‘Langra’, ‘Black Chaunsa’, ‘Sufaid Chaunsa’, ‘Sindhri’, ‘Malda’, ‘Anwar Ratul’, ‘Dusehri’, ‘Ratul-12’, ‘Tukhmi’ and ‘Sensation’ were studied for two years (2005-2007) in Multan District. The present studies revealed that ‘Chaunsa’ was the most susceptible cultivar with maximum population of mango mealybug i.e. 87.4 individuals per 30 cm of branch whereas minimum population was observed on Tukhmi i.e. 15.9 per 30 cm of branch. These studies provide compelling evidence that ‘Chaunsa’ is very amenable to the development and reproduction of the mango mealybug. Other cultivars were ranked from most susceptible to least susceptible as ‘Black Chaunsa’ > ‘Malda’ > ‘Fajri’ > ‘Ratul-12’ > ‘Langra’ > ‘Sensation’ > ‘Sindhri’ > ‘Dusehri’ > ‘Sufaid Chaunsa’ and ‘Anwar Ratul’ with 78.6, 72.9, 69.9, 60.7, 52.9, 48.5, 43.5, 31.9, 23.8 and 17.4 individuals per 30 cm of branch, respectively. Furthermore the southern side of the plant had significantly higher population of mango mealybug was found than east facing side. It was also observed that the peak activity period of the pest was 2 nd week of Feb. to 2 nd week of Mar. and the population decreased thereafter. The results of present studies are in contrast to already reported (Matokot et al., 1992). The most probable reason could be the differences in the methods used to carry out previous studies. The results of the presence of mealybug on various parts of mango tree suggest that on southern side maximum population of mango mealybug was present on leaves and inflorescence, while on the western side of the plant maximum numbers of mango mealybug was observed on branches. Maximum numbers of mealybugs were observed on mango tree than on non-target plants such as weeds. The likely speculate that the reason that mealybugs were more numerous on the south side of the tree has something to do with ambient temperature. Because of the angle of the sun, the insects on the south and east sides will get more degree day accumulation than insects on the west or north cardinal directions. It is recommended that during pest scouting, pest monitoring or
77 Chapter 4 Population Dynamics, Cultivar Resistance & Biology survey of the pests particularly mango mealybug, southern side of the plant should be sampled for better results. The present results are very much similar to the results of Dwivedi et al., (2003) who observed the highest numbers of mango mealybug at the base of the tree trunk than on weeds. The most probable reason could be that on weeds mealybug did not find the same amount of sap as on mango tree and also weeds may not be their preferred host plant. Parasitization and predation of the scales was generally higher during 2005-2006 compared to 2006-2007. Since the population of mealybug was higher in 2005-2006 to 2006-2007 therefore natural enemies had enough hosts to parasitize. In contrast Godfray, (1994), Benrey and Denno (1997) found higher parasitism percentage when the population was lower. To determine the impact of host plants on fitness of mango mealybug the hibernating females decending from tree were collected, weighed and the length and width were measured. The data on number of eggs laid per female, length and width of ovisac were also recorded for each cultivar. The data suggested that the female collected from ‘Chaunsa’ cultivar laid maximum number of eggs (336) while Anwar Ratul cultivar had minimum (156). Similarly, maximum weight gain, length and width of female and ovisac were observed on ‘Chaunsa’ cultivar than others. The most probable reason for such discrimination is that the ‘Chaunsa’ cultivar is the most susceptible and preferred host for mealybug therefore the insects had enough food to survive and gain weight. It is well established that higher the weight of female, the more fecund it will be. The data of trail on different cultivars corroborated with the farmers experience regarding susceptibility of some mango cultivars like ‘Chaunsa’. We also have found in the present studies that the ‘Chaunsa’ cultivar has higher percentage of carbohydrates than the other cultivars (Section III). This finding suggests that carbohydrates might be playing a role to trigger increased uptake of sap from the vegetative parts resulting more gained weight on ‘Chaunsa’ cultivar than others. The current findings add significantly to those of Balock and Kozuma (1964); Nachiappan and Bhaskaran (1984); Bagle and Prasad (1984); Pathak and Dhaliwal (1986); Khaire et al., (1987); Hasen et al., (1989); Angeles (1991); Dhaliwal et al., (1993); Singh (1993); Carvalho et al., (1996); Dhaliwal and Dilawari
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(1996); Salem et al., (2006), who studied host plant resistance against different insect pests on different hosts. Biology and Behaviour of Mango Mealybug on Chaunsa cultivar The development times for various instars were 57 days, 26 and 20 days for first, 2nd and 3rd instars, respectively. Nymphs were negatively geotropic and the first instar moved upward with an average speed of 12 cm per minute, 2 nd instar 17 cm per minute and 3 rd instar 37 cm per minute. The female laid eggs on an average of 282 in 29 days. In contrast, mango mealybug female was found to lay 336-, 372- and 300-eggs in the field (Rahman and Latif, 1944; Haq and Akmal, 1960; Chandra et al., 1987) and these variations could be due to weather conditions. Period of abundance The results of period of abundance suggest that the population was highest in the months of Feb. to Mar. in Multan. The most probable reason for the peak is favourable environmental condition in the area. Since the average temperature range between 11 to 24 oC with RH 79 percent conditions and these conditions were found to be suitable for the development of the pest. The present results are similar to Yadav et al., (2004) who observed higher number of mango mealybug population at average temperature of 27 oC with RH 50 percent but the population decreased with the increase in temperature. In contrast Yousuf and Gaur (1993) reported highest number of mango mealybug population in the months of June to July.
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ABSTRACT
The study was conducted to determine the role of various chemicals like nitrogen, potassium, crude fiber, fat, sodium, ash, carbohydrates, phosphorus, moisture and crude protein in tolerance to mango mealybug. The cultivars from which the population data of mango mealybug were collected i.e. ‘Chaunsa’, ‘Fajri’, ‘Langra’, ‘Black Chaunsa’, ‘Sufaid Chaunsa’, ‘Sindhri’, ‘Malda’, ‘Anwar Ratul’, ‘Dusehri’, ‘Ratul-12’, ‘Sensation’ and one seed born cultivar ‘Tukhmi’ were selected for biochemical analysis from district Multan during 2005-06 and 2006-07. The chemical contents varies from cultivar to cultivar however, carbohydrates were significantly higher in leaves of ‘Chaunsa’ cultivar, which was susceptible to mango mealybug, while Tukhmi, comparatively resistant to mango mealybug had significantly lower contents of carbohydrates. Furthermore, it was observed that crude fiber, fat, sodium, ash and crude protein showed negative significant correlation with the pest population on leaves, while carbohydrate and potassium had positive correlation with the pest population. All the chemical plant factors on leaves and inflorescence differed significantly among various cultivars of mango. All the other factors did not show any specific sequence with the population of the pest in all the cultivars. Key words: Cultivars, Chemical factors, leaves, Inflorescence, Mango mealybug
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5.1 INTRODUCTION
Plant resistance to insect pests is one of the most important components of the integrated pest management (IPM). A wide array of chemical substances including inorganic chemicals, primary and intermediary metabolites and secondary substances are known to impart resistance to a wide cultivar of insect pests. The host plant may also be deficient in certain nutritional elements required by the insects and hence prove resistant. A number of plant characteristics are known to render the cultivar less suitable or unsuitable for feeding, oviposition and development of insect pests. The nutritionally deficient plant may cause antibiotic and antixenotic effects on insect. Antibiosis may result from the absence of certain nutritional substances in the host plants, deficiency of some nutritional materials and /or imbalance of available nutrients.The objectives of these studies were to determine if various chemical viz., nitrogen, potassium, crude fibre, fat, sodium, ash, carbohydrates, phosphorus, crude protein in leaves and inflorescence could play an important role in regulating mango mealybug populations.
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5.2 MATERIALS AND METHODS
The leaves of ‘Chaunsa’, ‘Black Chaunsa’, ‘Fajri’, ‘Ratul-12’, ‘Malda’, ‘Langra’, ‘Sufaid Chaunsa’, ‘Dusehri’, ‘Anwar Ratul’, ‘Tukhmi’ and ‘Sensation’ cultivars were plucked from a 30 cm branch of the trees. The leaves were plucked from east, west, south and north sides of the selected cultivars from three different gardens at the time of insect data collected. The distance between gardens was ca 3-10 km. The leaves of each cultivar were kept separately in paper envelope in three repeats and thus the 36 samples of leaves were obtained from different cultivars. The leaves were brought to Bahauddin Zakariya University, Multan laboratory, clean them and weighed. These samples were kept in the oven for the determination of moisture contents. After drying, the leaves were ground in grinder and fine powder was obtained and used for the determination of chemical analysis. When the inflorescence comes out, the samples of inflorescence were also collected and processed as described for leaves. 5.2.1 MOISTURE CONTENT Freshly picked leaves were cleaned with muslin’s cloth and weighed. The leaves were then kept in an oven at 65 oC for 72 hours. After drying, leaves were weighed again and the percent moisture was calculated as given below. A − B Moisture (%) = × 100 A A = Weight of fresh leaves B = Weight of dried leaves 5.2.2 TOTAL MINERALS A 2g sample of dried leaf powder of each cultivar was placed in a boron-free fused silica crucible. The samples were burnt to ashes in muffle furnace at 600 oC for five hours. The dried matter after combustion was weighed again and placed back to same temperature until it was completely burnt to white ashes to a constant weight. The
82 Chapter 5 Biochemical Analysis of Mango Leaves & Inflorescence experiment was repeated four times. Total minerals were calculated using formula of Ranganna (1977). A Total Minerals (%) = × 100 B A = Weight of the ash B = Weight of dried leaves 5.2.3 NITROGEN 0.5 g of dried leaves tissue powder from each sample was taken to determine the nitrogen percentage by Kjeldahl Method. It was calculated by the formula (Winkleman et. al ., 1986). of N of acid x 14.007 x [ml of Titrant for sample - ml of titrant for blank] Nitrogen (%) = × 100 weight of smaple ()grams The procedure was repeated three times. 5.2.4 CRUDE PROTEIN The crude protein was calculated by the formula followed by Winklemqan et al., (1986) given as under: Crude Protein (%) = Nitrogen percent x 6.25 5.2.5 FAT CONTENTS Two grams of the bulk sample was taken in plugged thimble. Fat sample was extracted with solvent ether on Soxhlet extraction apparatus, for ten hours. The ether extract was dried and fats were calculated with the help of following formula (A.O.A.C., 1975). weight of ether extract Fats (%) = × 100 weight of sample 5.2.6 CRUDE FIBRE The small sample left behind after fat extraction was dried and digested with 1.25
percent H2SO 4 on crude fibre extraction apparatus. The digested material was then filtered, re-digested with N/10 NaOH and re-filtered. The materials left on the filter paper were dried and then ignited in muffle furnace for 30 minutes. After cooling for one hour in a desiccator’s, the ignited material was weighed. The loss in weight after ignition was
83 Chapter 5 Biochemical Analysis of Mango Leaves & Inflorescence measured and the crude fibre was calculated by using the following formula (A.O.A.C., 1975). loss in weight on ignition Crude fibre (%) = × 100 weight of the sample 5.2.7 SOLUBLE CARBOHYDRATES Following formula was used to determine the soluble carbohydrates (A.O.A.C., 1975). Soluble Carbohydrates (%) = 100 - crude protein+ percent fats + crude fibre + percent ashes. There were three replications for the determination of each component. 5.2.8 SAMPLE DIGESTION FOR MACRO NUTRIENTS One gram of the material from each sample was weighed to determine the
macronutrients and digested in 10 ml concentrated nitric acid (HNO 3) and an equal quantity of 72 percent perchloric acid (HCLO 4) was added. The volume was then reduced to 3 ml and the sample became colourless, it was placed on ice to lower the temperature and then transferred to volumetric flask. The volume was increased to 100 ml by adding distilled water. The samples were then filtrated and stored in falcon tubes for further analysis. 5.2.8.1 Phosphorus Phosphorus was determined by using the digested materials from previous section of samples following method 56 and 61 (Richard, 1954), respectively on Spectro Photometer AnA-720 w Tokyo, Photoelectric Co. Ltd. Japan using 470 mm wavelength as the characteristic band. 5.2.8.2 Potassium and Sodium These were determined by using the digested materials with the help of Methods 55a, 58a and 57 a (Richard, 1954), respectively on Flame Photometer, Jenway Ltd. Felsted CM6 3LB, DUNMOW ESSEX England. 5.2.9 STATISTICAL CORRELATIONS The effect of macro and micronutrients on mealybug population has been studied previously however in the present study I was interested to find out if there is
84 Chapter 5 Biochemical Analysis of Mango Leaves & Inflorescence correlationship between mealybug population and various nutrients in different parts of mango trees. Simple correlation was worked out between population and chemical factors individually and cumulatively by using Multiple Linear Regression Equation of the Type 1 viz., = a + b1x1+ X b2x2 X b3x3 X b4x4………………………where population of mealybug was taken as the Response Variables (Y) and the X represent the chemical factors in the equation. The data were analyzed on an IBM-PC Computer using M. Stat (Steel and Torrie, 1980) Package. Means were separated by Duncan’s New Multiple Range Test (DMRT) (Duncan, 1955).
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5.3 RESULTS AND DISCUSSION
Various biochemical factors such as nitrogen, potassium, crude fiber, fats, sodium, ashes, carbohydrate, phosphorus, moisture and crude protein in leaves and inflorescence of different cultivars of mango viz., ‘Chaunsa’, ‘Fajri’, ‘Langra’, ‘Black Chaunsa’, ‘Sufaid Chaunsa’, ‘Sindhri’, ‘Malda’, ‘Dusehri’, ‘Anwar Ratul’, ‘Ratul-12’, ‘Tukhmi’ and ‘Sensation’ in their leaves and inflorescence were determined and correlated with the population data with the objective to find the role of these factors towards resistance/susceptibility. The results are described below. 5.3.1 CHEMICAL FACTORS IN LEAVES OF DIFFERENT CULTIVARS OF MANGO 5.3.1.1 Nitrogen The results regarding nitrogen contents in the leaves of various cultivars of mango reveal significant differences between among various mango cultivars (Table 1, Column A). The maximum nitrogen content (3.0 percent) was observed in ‘Sufaid Chaunsa’ leaves which were significantly higher than ‘Dusehri’, ‘Ratul-12’, ‘Langra’ and ‘Anwar Ratul’, i.e. 2.1, 1.8, 1.6 and 1.6 percent nitrogen contents, respectively. The minimum nitrogen content was recorded to be 1.2 percent in the leaves of both ‘Tukhmi’ and ‘Fajri’ cultivars. Nonsignificant differences were found in the leaves of ‘Chaunsa’, ‘Black Chaunsa’ and ‘Sindhri’ with 1.6, 1.5 and 1.6 percent nitrogen, respectively. Similarly nitrogen content i.e. 1.4 percent each in the leaves of ‘Malda’ and ‘Tukhmi’ did not show significant difference with one another (Table 1).
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Table 1. MEAN COMPARISON OF THE DATA REGARDING CHEMICAL CONSTITUENTS (PERCENT) OF LEAVES IN DIFFERENT CULTIVARS OF MANGO
Crude Crude Nitrogen Potassium Fat Sodium Ash Carbohydrates Phosphorus Moisture Cultivars Fibre protein A** B** C** D** E** F** G** H** I** J** Anwar Ratul 1.64 d 1.078 fg 28 a 3.5 a 0.334 b 14 a 44.29 j 1.39 b 50.49 k 10.20 e Black 1.52 e 1.466 b 14 e 1.5 e 0.224 e 9 d 66.02 b 0.47 j 57.89 b 9.48 g Chaunsa Chaunsa 1.58 de 1.201 d 11 f 2.0 d 0.185 f 11 bc 66.16 a 0.42 k 60.60 a 9.84 f Dusehri 2.10 b 1.008 h 20 cd 2.5 c 0.259 d 14 a 50.37 h 1.17 d 54.58 e 13.13 c Fajri 1.23 g 1.192 d 19 cd 2.5 c 0.297 c 9 d 61.84 d 2.08 a 49.94 l 7.66 i Langra 1.64 d 1.034 .c 15 e 3.0 b 0.259 d 12 b 59.79 f 1.24 c 56.06 c 10.21 e Malda 1.40 f 2.748 a 14 e 3.0 b 0.222 e 12 b 62.25 c 0.97 e 50.70 j 8.75 h Ratul-12 1.75 c 1.080 fg 16 e 1.5 e 0.408 a 11 bc 60.59 e 0.62 g 51.56 i 10.94 d Sensation 1.40 f 1.158 de 18 d 3.5 a 0.222 e 10 cd 59.75 f 0.52 i 53.95 f 8.75 h Sindhri 1.58 de 1.123 ef 20 cd 2.5 c 0.258 d 10 cd 57.66 g 0.74 f 53.77 g 9.84 f Sufaid 3.04 a 1.060 gh 21 c 2.5 c 0.259 d 10 cd 47.54 i 0.57 h 55.68 d 18.96 a Chaunsa Tukhmi 1.23 g 1.096 fg 24 b 2.5 c 0.259 d 14 a 43.80 k 0.22 l 52.78 h 15.63 b LSD @ 5% 0.0927 0.0535 1.9718 0.1776 0.00535 1.725184 0.05354 0.016 0.1693 0.05354 F-value 256.7 566.1 49.6 118.2 3638.4 10.2 357907.2 220.6 3145.4 51535.0 Cultivar (n=12) Chemical constituents (n=10) df=11 Means sharing similar letters in columns A to J for means did not differ significantly by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
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5.3.1.2 Potassium The results relating to potassium contents in the leaves of various cultivars of mango show significant variations among cultivars (Table 1, Column B). The maximum potassium content (2.75 percent) was found in the leaves of ‘Malda’ and differed significantly from those of observed in the leaves of all other cultivars followed by 1.47, 1.03, 1.20, 1.19 and 1.15 percent potassium contents in the leaves of ‘Black Chaunsa’, ‘Langra’, ‘Chaunsa’, ‘Fajri’ and ‘Sensation’, respectively. The later mentioned figure in cultivar ‘Sensation’ also did not show significant variation with those of observed in the leaves of ‘Sindhri’ i.e. 1.12 percent potassium. Nonsignificant difference were found to exist among ‘Tukhmi’, ‘Ratul-12’, ‘Anwar Ratul’ and ‘Sufaid Chaunsa’ having 1.09, 1.08, 1.07 and 1.06 percent potassium contents in their leaves, respectively. The minimum potassium content was determined in the leaves of ‘Dusehri’ i.e. 1.01 percent and did not show significant difference with those of observed in the leaves of ‘Sufaid Chaunsa’ (1.06 percent). 5.3.1.3 Crude Fiber The results pertaining to crude fiber in the leaves of various cultivars of mango reveal significant difference among cultivars (Table 1, Column C). The maximum crude fiber contents (28.0 percent) was observed in the leaves of ‘Anwar Ratul’ and differed significantly from those of observed in the leaves of all other cultivars followed by 24.0, 21.0, 20.0, 20.0, 19.0 and 18.0 percent crude fiber contents in the leaves of ‘Tukhmi’, ‘Sufaid Chaunsa’, ‘Sindhri’, ‘Dusehri’, ‘Fajri’ and ‘Sensation’, respectively. The minimum crude fiber contents was found to be 11.00 percent in the leaves of ‘Chaunsa’ and differed significantly from those of observed in all other cultivars. Nonsignificant differences were found to exist among leaves of ‘Black Chaunsa’ (14.0 percent), Langra (15.0 percent), Malda (14.0 percent) and Ratul-12 (16.0 percent) in crude fiber contents. 5.3.1.4 Fat Contents Significant variations were found to exist among cultivars regarding fat contents in their leaves (Table 1, Column D). The maximum fat contents was found in the leaves of Anwar Ratul and Sensation with 3.5 percent each and differed significantly from those of observed in all other cultivars followed by 3.0 percent fat contents each in the leaves of ‘Malda’ and ‘Langra’. No significant differences were found to exist among ‘Fajri’,
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‘Sufaid Chaunsa’, ‘Sindhri’, ‘Dusehri’ and ‘Tukhmi’ each showing 2.5 percent fat contents in their leaves. The minimum fat content was found in the leaves of ‘Ratul-12’ and ‘Black Chaunsa’ each showing 1.5 percent fat contents. The cultivar ‘Chaunsa’ showed 2.0 percent fat contents in the leaves and differed significantly from those of observed in the leaves of all other cultivars. 5.3.1.5 Sodium Contents Differences were found to be significant among cultivars regarding sodium contents in their leaves (Table 1, Column E). The maximum sodium contents was observed in the leaves of ‘Ratul-12’ at 0.41 percent followed by 0.33 and 0.30 percent in the leaves of ‘Anwar Ratul’ and ‘Fajri’, respectively and showed significant difference with each other as well as from those of observed in all other cultivars. Nonsignificant differences was found to exist among ‘Langra’, ‘Sufaid Chaunsa’, ‘Sindhri’, ‘Dusehri’ and ‘Malda’ showed 0.26, 0.26, 0.26, 0.26 and 0.26 percent sodium contents in their leaves, respectively. The cultivar ‘Chaunsa’ possessed the lowest sodium percentage in the leaves i.e. 0.19 and differed significantly from those of observed in leaves all other cultivars as well as in the leaves of Sensation with 0.22 percent sodium contents. 5.3.1.6 Ash Contents The results regarding ash contents in the leaves of different cultivars of mango reveal significant variations among cultivars (Table 1, Column F). The leaves of ‘Tukhmi’, ‘Anwar Ratul’ and ‘Dusehri’ showed maximum ash contents i.e. 14.00 percent each followed by 12.00 percent in the leaves of each ‘Langra’ and ‘Malda’. The cultivar ‘Ratul-12’ and ‘Chaunsa’ each contained 11.00 percent ash contents in the leaves and showed nonsignificant difference with those of observed in the leaves of ‘Sensation’, ‘Sindhri’ and ‘Sufaid Chaunsa’ each contained 10.00 percent ash contents as well as with those of observed in the leaves of ‘Langra’ and ‘Malda’. Non significant difference was also observed in the leaves of ‘Fajri’ and ‘Black Chaunsa’ each showed 9.00 percent ash contents and was statistically at par with the contents in the leaves of ‘Sufaid Chaunsa’, ‘Sindhri’ and ‘Sensation’. 5.3.1.7 Carbohydrate All the cultivars of mango differed significantly with one another regarding carbohydrate contents in their leaves (Table 1, Column G). The cultivar ‘Chaunsa’ had
89 Chapter 5 Biochemical Analysis of Mango Leaves & Inflorescence the highest carbohydrates in the leaves i.e. 66.2 percent followed by 66.0, 62.3 and 61.8 percent in the leaves of ‘Black Chaunsa’, ‘Malda’ and ‘Fajri’, respectively. The lowest carbohydrate was observed in the leaves of ‘Tukhmi’ i.e. 43.8 percent and also differed significantly from those of observed in the leaves of all other cultivars. Nonsignificant variation was found to exist between ‘Langra’ and ‘Sensation’ showing 59.8 and 59.8 percent carbohydrates in their leaves, respectively. The cultivar ‘Ratul-12’, ‘Sindhri’, ‘Dusehri’ and ‘Anwar Ratul’ contained 60.6, 50.4, 47.5 and 44.3 percent carbohydrates in their leaves, respectively and were differed significantly from each other. 5.3.1.8 Phosphorus The results regarding phosphorus contents in the leaves of various mango cultivars reveal significant variation among cultivars (Table 1, Column H). The maximum phosphorus contents was observed to be 2.1 percent in the leaves of ‘Fajri’ and differed significantly from those of observed in the leaves of all other cultivars of mango. The minimum phosphorus content was found to be 0.2 percent in the leaves of ‘Tukhmi’ and also differed significantly from those of observed in the leaves of all other cultivars. The phosphorus contents in descending order were 1.4, 1.2, 1.2, 1.0, 0.7, 0.6, 0.6, 0.5, 0.5 and 0.4 percent in the leaves of ‘Anwar Ratul’, ‘Langra’, ‘Dusehri’, ‘Malda’, ‘Sindhri’, ‘Ratul-12’, ‘Sufaid Chaunsa’, ‘Sensation’, ‘Black Chaunsa’ and ‘Chaunsa’, respectively. 5.3.1.9 Moisture The results relating to moisture percentage in the leaves of various mango cultivars showed significant variation among cultivars (Table 1, Column I). Maximum moisture percentage was recorded to be 60.6 in the leaves of ‘Chaunsa’ followed by 57.9 56.1, 55.7, 54.6, 54.0, 54.0, 53.0, 51.6, 50.7 and 50.5 percent in the leaves of ‘Black Chaunsa’, ‘Langra’, ‘Sufaid Chaunsa’, ‘Dusehri’, ‘Sensation’, ‘Sindhri’, ‘Tukhmi’, ‘Ratul-12’, ‘Malda’ and ‘Anwar Ratul’, respectively and all these showed significant difference from each other. The minimum moisture percentage was observed to be 49.9 in the leaves of ‘Fajri’ and also showed significant variation from those of observed in the leaves of all other cultivars of mango. 5.3.1.10 Crude Protein . The results relating to crude protein in the leaves of various cultivars of mango reveal significant difference among cultivars (Table 1, Column J). The maximum crude
90 Chapter 5 Biochemical Analysis of Mango Leaves & Inflorescence protein was observed in the leaves of ‘Sufaid Chaunsa’ i.e. 19.0 percent followed by 15.6, 13.1 and 14.9 percent in the leaves of ‘Tukhmi’, ‘Dusehri’ and ‘Ratul-12’, respectively. No significant differences were found to exist between ‘Chaunsa’ and ‘Sindhri’ each showing 9.8 percent crude protein in their leaves. Similarly ‘Langra’ and ‘Anwar Ratul’ did not show significant difference regarding crude protein in their leaves showing 10.2 and 10.2 percent, respectively. The protein contents were 8.8 percent in the leaves of each ‘Malda’ and ‘Sensation’ and also showed nonsignificant difference from one another. The minimum crude protein was found to be 7.7 percent in the leaves of ‘Fajri’ and showed significant difference with those of observed in the leaves of ‘Black Chaunsa’ i.e. 9.5 percent and as well as from those of observed in all other cultivars. 5.3.2 CHEMICAL FACTORS IN INFLORESCENCE IN DIFFERENT CULTIVARS OF MANGO 5.3.2.1 Nitrogen The data regarding nitrogen percentage in the inflorescence of different cultivars of mango are given in Table 2, Column A. The results reveal significant differences among cultivars. The cultivar ‘Tukhmi’ showed maximum nitrogen percentage in inflorescences i.e. 2.0 and showed significant difference with those of observed in all other cultivars followed by 1.9 percent nitrogen contents in inflorescences of each ‘Dusehri’, ‘Malda’, ‘Langra’ and ‘Chaunsa’ which were statistically similar with one another. The minimum nitrogen content was found to be 1.6 percent in the inflorescence of each ‘Black Chaunsa’ and ‘Ratul-12’ which also showed nonsignificant difference with each other. The cultivars ‘Sufaid Chaunsa’, ‘Anwar Ratul’ and ‘Sensation’ did not show significant difference with one another regarding nitrogen contents with 1.6, 1.6 and 1.6 percent, respectively. The later mentioned figure also showed nonsignificant variation with those of observed in ‘Ratul-12’ and ‘Black Chaunsa’. The cultivars ‘Fajri’ and ‘Sindhri’ possessed 1.9 and 1.8 percent nitrogen percentage in their inflorescence and differed significantly with each other. 5.3.2.2 Potassium The results (Table 2, Column B) reveal significant variation among cultivars regarding potassium contents in their inflorescence. The cultivar ‘Malda’ had significantly the highest potassium contents followed by 1.9, 1.9, 1.9, 1.9 and 1.8 percent in the inflorescence of ‘Fajri’, ‘Sensation’, ‘Sindhri’, ‘Sufaid Chaunsa’ and ‘Black
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Chaunsa’, respectively and did not differ significantly with one another. Minimum content of potassium was observed to be 1.6 percent in the inflorescence of ‘Chaunsa’ and did not show significant difference with 1.6 percent in ‘Langra’. Similarly ‘Anwar Ratul’ and ‘Ratul-12’ showed no significant difference from each other having 1.7 and 1.8 percent potassium, respectively. Also no significant difference was also observed in the inflorescence of ‘Tukhmi’ and ‘Dusehri’ with 1.5 and 1.5 percent potassium content, respectively. 5.3.2.3 Crude Fibre The results presented in (Table 2, Column C) reveal significant differences among mango cultivars regarding crude fiber contents. The maximum contents of crude fiber was observed to be 12.0 percent in the inflorescence of each ‘Fajri’, ‘Malda’ and ‘Anwar Ratul’ and showed nonsignificant difference with 11.0, 11.0, 11.0, 10.0 and 10.0 crude fiber contents in the inflorescence of ‘Tukhmi’, ‘Ratul-12’, ‘Dusehri’, ‘Sindhri’ and ‘Sufaid Chaunsa’, respectively. The cultivars ‘Chaunsa’, ‘Black Chaunsa’ and ‘Langra’ each had 8.0 percent crude fiber in their inflorescence and did not differed significantly from ‘Sensation’ 7.0 percent crude fiber in the inflorescence. 5.3.2.4 Fat Contents The results pertaining to fat contents in the inflorescence of various cultivars reveal significant difference among cultivars (Table 2, Column D). ‘Anwar Ratul’ and ‘Sensation’ had the highest fat contents with 3.5 percent each. These cultivars were followed by ‘Malda’ and ‘Sufaid Chaunsa’ with 3.0 and 2.5 percent fat contents respectively. ‘Malda’ and ‘Sufaid Chaunsa’ and differed significantly with one another as well as with ‘Anwar Ratul’ and ‘Sensation’. Fat contents of 1.5 percent was found in the inflorescence of each ‘Chaunsa’, ‘Fajri’, ‘Langra’, ‘Black Chaunsa’, ‘Sindhri’, ‘Ratul-12’ and ‘Tukhmi’ had the same fat content (1.5 percent). The lowest fat content was found in the inflorescence of ‘Dusehri’ at 1.0 percent and differed significantly from those of observed in all other cultivars. 5.3.2.5 Sodium Significant variations were found to exist among cultivars regarding sodium contents in their inflorescence (Table 2, Column E). The lowest sodium content was found to be 0.223 percent in the inflorescence of ‘Tukhmi’ and this differed significantly
92 Chapter 5 Biochemical Analysis of Mango Leaves & Inflorescence from those of observed in all other cultivars. No significant difference was found to exist between ‘Chaunsa’, ‘Langra’, ‘Sufaid Chaunsa’, ‘Sindhri’ and ‘Anwar Ratul’ each possessed 0.19 percent sodium contents in their inflorescence. Similarly nonsignificant variation was found to exist among ‘Ratul-12’, ‘Dusehri’, ‘Malda’, ‘Black Chaunsa’ and ‘Fajri’ all contained 0.15 percent sodium content in their inflorescence and categorized as intermediate. 5.3.2.6 Ash Contents The data regarding ash content in the inflorescence of various cultivars of mango are given in (Table 2, Column F). The results reveal that highest ash contents were observed in the inflorescence of ‘Tukhmi’ (7 percent) and ‘Chaunsa’ (6 percent). All the other cultivars had significantly lower ash content. These other varieities did not differ significantly regarding ash content present in their inflorescence and ranged from 2 to 4 percent. 5.3.2.7 Carbohydrate Significant differences were found to exist among cultivars of mango regarding carbohydrates present in their inflorescence (Table 2, Column G) The highest carbohydrate level was observed in the inflorescence of ‘Sensation’ (79.3 percent) and followed by the inflorescences of ‘Black Chaunsa’, ‘Sufaid Chaunsa’ and ‘Ratul-12’ with 77.7, 75.8 and 75.7 percent carbohydrate, respectively. The later mentioned figures also differed significantly from one another. The lowest carbohydrate was observed in the inflorescence of ‘Tukhmi’ (58.8 percent) and this differed significantly from other cultivars of mango tested viz., ‘Chaunsa’, ‘Fajri’, ‘Langra’, ‘Sindhri’, ‘Malda’, ‘Dusehri’ and ‘Anwar Ratul’ with 72.5, 70.8, 71.5, 74.6, 70.5, 74.0 and 73.4 percent carbohydrates in their inflorescence, respectively and ranked as intermediate.
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Table 2. MEAN COMPARISON OF THE DATA REGARDING CHEMICAL CONSTITUENTS (PERCENT) OF INFLORESCENCE IN DIFFERENT CULTIVARS OF MANGO
Crude Nitrogen Potassium Crude fibre Fat Sodium Ash Carbohydrates Phosphorus Cultivars protein A** B** C** D** E** F** G** H** I** Anwar Ratul 1.64 e 1.73 e 12 a 3.50 a 0.185 b 3 b 73.43 g 4.12 e 10.57 e Black Chaunsa 1.58 f 1.84 cd 8 b 1.50 d 0.148 c 3 b 77.66 b 7.51 b 9.78 h Chaunsa 1.92 b 1.60 f 8 b 1.50 d 0.185 b 6 a 72.47 h 3.52 i 12.03 b Dusehri 1.92 b 1.49 g 11 a 1.00 e 0.148 c 2 b 73.97 f 4.02 g 12.03 b Fajri 1.86 c 1.93 b 12 a 1.50 d 0.148 c 4 b 70.83 j 3.35 j 11.67 c Langra 1.92 b 1.63 f 8 b 1.50 d 0.185 b 4 b 71.47 i 2.28 l 12.03 b Malda 1.92 b 2.13 a 12 a 3.00 b 0.148 c 4 b 70.47 k 7.42 c 12.03 b Ratul-12 1.58 f 1.78d e 11 a 1.50 d 0.148 c 2 b 75.66 d 5.46 d 9.84 g Sensation 1.60e f 1.90 bc 7 b 3.50 a 0.148 c 3 b 79.25 a 9.89 a 8.75 i Sindhri 1.75 d 1.89 bc 10 a 1.50 d 0.185 b 3 b 74.56 e 3.67 h 10.94 d Sufaid Chaunsa 1.64 e 1.87 bc 10 a 2.50 c 0.185 b 3 b 75.79 c 4.09 f 10.21 f Tukhmi 2.04 a 1.52 g 11 a 1.50 d 0.223 a 7 a 58.78 l 2.78 k 12.76 a Lsd @5% 0.05354 0.07572 1.7686 0.05354 0.01693 1.7686 0.01693 0.01693 0.05354 F-value 256.7 566.1 49.6 118.2 3638.4 10.2 357907.2 220.6 51535.0 Cultivar (n=12) Chemical constituents (n=9) df=11 Means sharing similar letters in columns A to I for means did not differ significantly by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
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5.3.2.8 Phosphorus Significant variations were found to exist among cultivars regarding phosphorus content in their inflorescence (Table 2, Column H). The cultivar ‘Sensation’ showed the highest phosphorus content and differed significantly from those of observed in all other cultivars. The lowest phosphorus contents was found to be 2.3 percent in the inflorescence of ‘Langra’ cultivar and also showed significant variations from those of observed in all other cultivars. The descending position of other cultivars were ‘Black Chaunsa’, ‘Malda’, ‘Ratul-12’, ‘Anwar Ratul’, ‘Sufaid Chaunsa’, ‘Dusehri’, ‘Sindhri’, ‘Chaunsa’, ‘Fajri’ and ‘Tukhmi’ with 7.5, 7.4, 5.5, 4.1, 4.1, 4.0, 3.7, 3.5, 3.4 and 2.8 percent phosphorus contents, respectively and all these cultivars differed significantly with one another. 5.3.2.9 Crude Protein The highest crude protein observed was 12.8 percent in the inflorescence of ‘Tukhmi’ and this differed significantly from those of found in all other cultivars and followed by 12.0 percent crude protein for ‘Dusehri’, ‘Malda’, ‘Langra’, and ‘Chaunsa’ (Table 2, Column I). The lowest crude protein was found to be 9.8 percent in the inflorescence of ‘Black Chaunsa’ which was significantly greater than observed in the inflorescence of all other cultivars of mango. The descending position of other cultivars was ‘Fajri’, ‘Sindhri’, ‘Anwar Ratul’, ‘Sufaid Chaunsa’ and ‘Ratul-12’ with 11.7, 10.9, 10.6, 10.2 and 9.5 percent crude protein in their inflorescence, respectively, and all differed significantly from one another statistically. 5.3.3 IMPACT OF VARIOUS CHEMICAL FACTORS ON THE POPULATION OF MANGO MEALYBUG Various chemical factors determined from the leaves and inflorescence of different mango cultivars were correlated with the respective populations on the leaves and inflorescence. The same parameters were processed for multiple linear regression models through steps to see the impact of chemical factors and also determined the role of individual chemical factors in the fluctuation of the population of mango mealybug on the leaves and inflorescence. The results are presented under the following sub-sections. 5.3.3.1 Simple Correlation The results presented in Table 3 reveal that crude fiber, fat, sodium, ashes and crude protein contents showed negative and significant correlation with the population of
95 Chapter 5 Biochemical Analysis of Mango Leaves & Inflorescence mango mealybug on leaves, whereas carbohydrate and potassium had significant and positive correlation with the population of the pest. Nitrogen, phosphorus and moisture percentage did not show significant correlation with the population of mango mealybug. All the chemical plant factors resulted nonsignificant correlation with the population of mango mealybug on inflorescence except crude fiber and nitrogen. Crude fiber showed negative, whereas nitrogen showed positive and significant correlation with the pest population. Table 3. SIMPLE CORRELATION BETWEEN POPULATION OF MEALYBUG ON MANGO LEAVES AND INFLORESCENCE ALONG WITH BIOCHEMICAL FACTORS.
Constituents Leaves Inflorescence Ash -0.595** 0.225 Carbohydrate 0.257** 0.133 Crude fibre -0.884** -0.340* Crude protein -0.664** -0.034 Fat 0.400** -0.134 Moisture 0.300 - Nitrogen -0.293 0.369* Phosphorus 0.101 0.136 Potassium 0.482** 0.305 Sodium -0.317* -0.152 Leaves (n=10) and Inflorescence constituents (n=9) *= Significant at P < 0.05. ** = Significant at P < 0.01.
5.3.3.2 Multiple Linear Regression Models 5.3.3.2.1 Impact of Chemical Factors in Population Fluctuation of Mango Mealybug on Leaves The results regarding multiple linear regression models between population fluctuation of mango mealybug on leaves and chemical factors along with coefficient of determination value are presented in Table 4. The results reveal that nitrogen content showed 8.6 percent role in the population fluctuation of mango mealybug and the impact was found to be nonsignificant. With the addition of potassium contents this role
96 Chapter 5 Biochemical Analysis of Mango Leaves & Inflorescence increased up to 25.9 percent in population fluctuation of the pest. The individual contribution of potassium was calculated to be 17.3 percent. The impact of potassium was however highly significant. Crude fiber exerted maximum contribution i.e. 55.8 percent in the population fluctuation for the pest and found to be the most important chemical. All the other factors were not so important which contributed 0.0 to 8.3 percent role in the population fluctuation of the pest. From these results it was observed that the effect of all the factors when computed together resulted in 96.5 percent contribution in population fluctuation of the pest. Therefore, it was concluded that all the factors when computed together contributed a significant role towards the resistance/susceptibility rather than a single factor.
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Table 4. MULTIPLE LINEAR REGRESSION MODELS BETWEEN POPULATION OF MEALYBUG ON MANGO LEAVES AND BIOCHEMICAL FACTORS ALONG WITH COEFFICIENT OF DETERMINATION VALUES.
Regression Equation D.F. F- P- R2 Individual value value Role (%) Y = 16.03 – 4.54 X1 34 2.78 0.08 0.086 8.6 X1 **Y= 4.37 – 2.63 X1 + 6.66 X2** 33 2.70 0.004 0.259 17.3 X2 **Y= 27.07 - 2.56 X1* + 1.08 X2- 3.57 X3 32 3.17 0.001 0.187 55.8 X3 **Y= 27.37-2.64 X1* + 1.63 X2 -3.33 X3**- 31 2.50 0.001 0.823 0.6 X4 1.13 X4 **Y= 21.75 - 2.61 X1* + 1.65X2 -3.57 30 2.16 0.001 0.854 3.30 X5 X3**-0.68 X4 + 6.63 X5 **Y= 25.52 - 2.50 X1** + 2.16 X2*- 29 2.21 0.002 0.906 5.2 X6 3.11X3**-0.02 X4 + 8.09 X5 - 2.52 X6** **Y= 26.22-2.25 X1**+1.94 X2-3.16 X3**- 28 2.37 0.003 0.906 0.0 X7 0.01 X4 + 8.18 X5-2.58 X6**-0.05 X7 **Y= 34.47-2.44 X1**+1.61 X2-2.03 X3**- 27 2.38 0.005 0.938 3.2 X8 1.50 X4-3.70 X5-2.25 X6**-0.07 X7+2.48 X8** **Y= 26.05-2.67 X1**+2.07 X2-2.77 X3**- 26 2.43 0.004 0.938 0.0 X9 1.39 X4-1.03 X5-2.31 X6-0.07 X7** +2.57 X8** +0.70X9 **Y= 45.40+1.58 X1+1.02 X2-2.36 X3**- 25 3.59 0.003 0.965 3.5 X10 2.71 X4**-8.84 X5-1.48 X6**-0.11 X7+1.02 X8-0.70 X9-2.15 X10** Where X1 =Nitrogen X2 =Potassium X3 =Crude fibre X4=Fat X5 =Sodium X6 =Ash X7 =Carbohydrates X8=Phosphorus X9 =Moisture X10=Crude Protein * = Significant at P < 0.05. ** = Significant at P < 0.01.
5.3.3.2.2 Impact of Chemical Factors in Population Fluctuation of Mango Mealybug on Inflorescence Linear multiple regression models between population fluctuation of mango mealybug on inflorescence and different chemical factors (Table 5) indicated that nitrogen content had a significant impact on the population fluctuation of the pest and explained 13.6 percent of the variation in the insect fluctuation. Ash content explained 26.4 percent of the variation in the population fluctuation of the pest and was found to be the most important factor. The coefficient of determination value was calculated to be
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0.54 when the effects of all the chemical factors were computed together. It was again concluded here that a combination of factors may contributed a significant impact on the population fluctuation of mango mealybug rather than a single factor. Table 5. LINEAR MULTIPLE REGRESSION MODELS BETWEEN POPULATION OF MEALYBUG ON MANGO INFLORESCENCE AND BIOCHEMICAL FACTORS ALONG WITH COEFFICIENT OF DETERMINATION VALUES.
Regression Equation D.F. F- P- R2 Individual value value Role (%) *Y = -4.96+3.59* X1 34 1.46 0.03 0.136 13.6 X1 Y = -5.80+3.23 X1+1.37 X2 33 0.31 0.73 0.137 0.1 X2 Y = -1.12+1.54 X1+3.73 X2-1.59 X3 32 2.47 0.07 0.179 4.2 X3 Y = -9.18+3.66 X1+2.96 X2-2.25 X3+1.36 31 2.28 0.08 0.237 5.8 X4 X4 Y = -9.49+3.68 X1+2.99 X2-2.25 X3+1.35 30 1.77 0.14 0.237 0.0 X5 X4+0.02 X5 **Y = -36.24+4.89 X1+0.61 X2-3.47 X3**+ 29 1.15 0.01 0.483 26.4 X6 0.33 X4 +0.39 X5+18.12 X6** **Y = -36.00+5.05 X1-0.04 X2-3.48 X3**+ 28 1.67 0.00 0.497 1.4 X7 0.46 X4+0.35 X5+18.15 X6**+0.17 X7 **Y = -35.52 +5.07 X1-0.62 X2-3.51 X3** 27 2.45 0.00 0.498 0.1 X8 +0.46 X4+0.35 X5+18.26**X6+0.17 X7+0.12 X8 **Y = -36.64+6.81 X1-1.63 X2-2.99 X3**+ 26 2.86 0.00 0.539 4.1 X9 0.22 X4+0.32 5+19.75**X6+0.09X7- 0.24 X8-1.45 X9 Where X1 =Nitrogen X2 =Potassium X3 =Crude fibre X4=Fat X5 =Sodium X6 =Ash X7 =Carbohydrates X8=Phosphorus X9 =Protein * = Significant at P < 0.05. ** = Significant at P < 0.01.
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5.4 DISCUSSION
A study was conducted to determine the role of various chemicals like nitrogen, potassium, crude fiber, fat, sodium, ash, carbohydrates, phosphorus, moisture and crude protein in tolerance to mango mealybug. The chemical contents varies from cultivar to cultivar however, carbohydrates were significantly higher in leaves of ‘Chaunsa’ cultivar, which was susceptible to mango mealybug, while Tukhmi, comparatively resistant to mango mealybug had significantly lower contents of carbohydrates. The present findings are similar to that of Haviland et. al. (2006) who reported that increased concentration of carbohydrates affecting the population of gill’s mealybugs (Ferrisia gilli ). The mealybugs having strawlike mouth parts through which it feed on the carbohydrates available in the juices of the plants. During the late summer and spring they like to feed on the stem of plant bearing flowers and cluster, respectively, where they rob the carbohydrates from the tree, which is necessary for fruit development. Further Busgen 1891 proposed the role of carbohydrates in a slightly different way. He reported that the insects attempted to obtain needed supply of protein, which apparently was present in small quantities in plant sap; in the process of obtaining the protein supply, excess carbohydrates and water were imbibed, and these were eliminated as honeydew. Furthermore, it was observed that crude fiber, fat, sodium, ash and crude protein showed negative significant correlation with the pest population on leaves, while carbohydrate and potassium had positive correlation with the pest population. Similarly the pest population on inflorescence showed no significant correlation with most of the chemicals analyzed. Linear Multiple Regression Models showed that crude fiber was the most important content in leaves which played a maximum role i.e. 55.80 percent in population fluctuation of mango mealybug on leaves followed by potassium, sodium, nitrogen, crude protein, phosphorus and fat contents. In case of pest population recorded on inflorescence, ash contents showed maximum contribution i.e. 26.04 percent in population fluctuation of the pest followed by nitrogen, fat, crude fiber, protein, phosphorus and potassium. In contrast to my findings, Tobih et al., (2002) have shown
100 Chapter 5 Biochemical Analysis of Mango Leaves & Inflorescence that mealybug infestation caused significant reduction in the crude fiber, ash content and reducing sugar level of both unripe and ripe fruits compared with controls. To the best of my knowledge there is no documented case where it has been shown that carbohydrates play an important role in infestation of mango mealybug. Though we do not have direct evidence to prove that carbohydrates increased mango mealybug infestations on the tree but we found the highest number of mango mealybug on ‘Chaunsa’ cultivar, which had significantly high level of carbohydrates content. This suggests that carbohydrate content might may play a role in mealybug abundance. However, further studies where application of carbohydrates from ‘Chaunsa’ cultivar onto a resistant cultivar could prove that susceptibility in ‘Chaunsa’ cultivar is due to carbohydrates.
101
ABSTRACT
The study was conducted to determine the yield loss caused by mango mealybug Drosicha mangiferae G. (Hemiptera:Monophlebidae) in different cultivars of mango based on number of fruits in treated versus untreated inflorescence of selected plants for each cultivar during 2006-2007 at Multan. No significant differences were found to exist among cultivars regarding number of fruits per inflorescence at initial stage of the experiment. The maximum loss in fruit yield was observed to be 11 percent in cultivar ‘Anwar Ratul’ at initial stage of the experiment followed by 11, 10, 10, 9, 9, 8 and 8 percent yield losses on ‘Ratul-12’, ‘Chaunsa’, ‘Black Chaunsa’, ‘Sindhri’, ‘Tukhmi’, ‘Dusehri’ and ‘Fajri’, respectively. The cultivars ‘Malda’, ‘Sufaid Chaunsa’, ‘Sensation’ and ‘Langra’ showed 6, 5, 5 and 3 percent yield losses, respectively at initial stage of the experiment. At final stage of the experiment ‘Chaunsa’ cultivar suffered the maximum yield loss showing 81 percent yield losses followed by 72, 69, 64, 52, 46, 35, 29, 24, 23, 22 and 18 percent yield losses on ‘Langra’, ‘Fajri’, ‘Ratul-12’, ‘Sufaid Chaunsa’, ‘Malda’, ‘Sensation’, ‘Dusehri’, ‘Sindhri’, ‘Black Chaunsa’, ‘Tukhmi’ and ‘Anwar Ratul’, respectively. Maximum population recorded on ‘Chaunsa’ cultivar was 18/inflorescence and minimum on ‘Anwar Ratul’ was 10/inflorescence. Key words: Mango cultivars, Loss in fruits, Drosicha mangiferae , Population.
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6.1 INTRODUCTION
Mealybugs are one of the most active groups of scale insects, however they generally remain on host plant once a suitable feeding site is found. Feeding by mealybugs can cause dieback, premature leaf drop and may even kill plants if left unchecked. Immatures and females scales of this pest suck the sap from mango inflorescence, tender leaves, shoots and fruit peduncles. Mealybug feeding causes inflorescence to shrivel and dry. The mealybug acquired the position of being the worst agricultural insect pest in the tropics (Herren, 1981). In addition to sucking sap from host plants, mealybugs also secrete honeydew, which serves as a medium for the growth of sooty mold fungus (Tandon and Lal, 1978) that reduces the plant's photosynthetic abilities (Pruthi & Batra, 1960; Smith et al., 1997; Pitan et al., 2000) rendered the fruit shape which become unsaleable (CAB International, 2005) and decreased the export values of mangoes (Willink and Moore, 1988). But in mango orchards the mealybug, Drosicha mangiferae is one of the most serious pests in sub-continent and is a growing threat to the fruit crops especially mango (Karar et al., 2006). It is responsible for devastating the crop during its serious incidence. The present study was planned to investigate the yield losses caused in mango due to D. mangiferae.
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6.2 MATERIALS AND METHODS
The experiment was performed to study the losses caused by mango mealybug in different cultivars for the year 2006-07. Three full-grown orchards (age 15-18 years) having all cultivars of mango under study were selected. The distance between one orchard to another was about two km. Six plants of each cultivar from each orchard were selected and three of these plants were treated to control mango mealybug while three were left untreated.Twenty inflorescence/plant from the east, west and south side of each tree, at a height of 4 to 6 feet above ground level, were tagged and the number of fruits developed was counted. The population data of mealybug were also recorded from the tagged inflorescence. The practices applied for the control of mealybug on mango trees are as follows: Name of treatment Date of application Impact Cultural control Mounds Developed on April 5, Destruction of eggs 2006 Spread on soil on June 28, 2006 Mechanical control Band December 10,2006 To stop crawling of first Plastic sheet 9 inch having instar nymphs upwards on 1.5 inch layer of grease in the tree the middle of plastic sheet Chemical control Acetamiprid 20SP@100g February 3,2007 Spray below the band to (a.i.20g)/100 liter water control aggregated nymphs The data for the number of fruits in treated and untreated trees were counted at maturity . The percent loss in yield for each cultivar was determined using following formula : Loss in Fruit yield (percent) = No. of fruits in Treated tree - No. of fruits in untreated trees × 100 number of fruits in treated trees The data on initial fruits and final fruits were analyzed through Randomized Complete Block Design.
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6.3 RESULTS AND DISCUSSION
The study was conducted to determine the yield loss caused by mango mealybug in different cultivars of mango based on number of fruits in treated versus untreated inflorescence of selected plants for each cultivar. The results are presented under the following sub-section. 6.3.1 INITIAL MANGO FRUITS IN TREATED AND UNTREATED TREES The data regarding number of fruits per inflorescence in different cultivars of mango in treated and nontreated plants are given in Table 1. The results reveal significant difference among cultivars and between treated and nontreated trees. The interaction response was found to be nonsignificant. In general nontreated trees of all the cultivars showed less mango fruits as compared to treated trees of the same cultivars. The maximum decrease of 11 percent mango fruit was recorded on ‘Anwar Ratul’ followed by 11, 10, 10, 9, 8 and 8 percent on ‘Ratul-12’, ‘Chaunsa’, ‘Black Chaunsa’, ‘Tukhmi’, ‘Malda’ and ‘Fajri’ respectively. The minimum decrease in fruit formation was recorded in cultivar ‘Langra’ and ‘Tukhmi’ with 3 and 3 percent, respectively. On overall basis it was observed that nontreated trees showed 8 percent decrease in fruits over treated trees.
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Table 1. MEANS COMPARISON OF THE DATA REGARDING NUMBER OF MANGO FRUITS PER INFLORESCENCE IN TREATED AND NONTREATED TREES AT INITIAL STAGE ON DIFFERENT CULTIVARS OF MANGO.
Fruits/inflorescence (**) Percent LSD = 0.68 reduction Name of Cultivar Nontreated Treated in Initial Fruit over treated Anwar Ratul 3.05 hijk 3.42 ghi 10.82 Black Chaunsa 4.27 cdef 4.72 c 9.53 Chaunsa 2.72 ijk 3.03 hijk 10.23 Dusehri 3.48 fghi 3.80 efgh 8.42 Fajri 2.50 k 2.60 jk 7.75 Langra 3.62 cd 3.75 efgh 3.47 Malda 3.72 efgh 3.95 defg 5.82 Ratul-12 3.30 ghij 3.70 efgh 10.81 Sensation 5.53 ab 5.73 a 3.49 Sindhri 4.43 cde 4.89 bc 9.41 Sufaid Chaunsa 3.52 fgh 3.70 efgh 4.61 Tukhmi 3.55 fgh 3.91 defg 9.21 Means 3.72 3.93 Cultivar (n=12) F-value=24.32 DF=11 Means sharing similar letters in interactional column are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
6.3.2 MANGO FRUITS OBTAINED AT MATURITY IN TREATED AND UNTREATED TREES The data regarding number of fruits obtained at maturity in nontreated and treated trees of different cultivars are given in Table 2. The results reveal significant variation among cultivars, between treated and nontreated trees and in their interactions. The fruits obtained in nontreated trees of all the cultivars showed significantly lower number of fruits as compared to treated trees of all the cultivars of mango. On overall basis the
106 Chapter 6 Losses Caused by Mango Mealybug decrease in fruit in untreated trees over treated trees was observed to be 44 percent. On individual basis the greatest fruit loss was found to be 81 percent on ‘Chaunsa’ cultivar followed by ‘Langra’, ‘Fajri’, ‘Ratul-12’, ‘Sufaid Chaunsa’, ‘Malda’ and ‘Sensation’ with 72, 69, 64, 52, 46 and 35 percent, respectively. The decrease in fruit in nontreated trees over treated trees was 18, 22, 23, 24 and 29 percent on ‘Anwar Ratul’, ‘Tukhmi’, ‘Black Chaunsa’, ‘Sindhri’ and ‘Dusehri’, respectively. Table 2. MEANS COMPARISON THE DATA REGARDING NUMBER OF MANGO FRUITS OBTAINED IN NONTREATED AND TREATED TREES AT MATURITY ON DIFFERENT CULTIVARS OF MANGO.
Percent Fruits obtained at harvest (**) reduction in LSD = 0.68 Name of Cultivar Final Yield over Nontreated Treated treated Anwar Ratul 2.08 gh 2.550 cde 18.43 Black Chaunsa 2.45 cdef 3.167 b 22.71 Chaunsa 0.40 l 2.057 gh 80.58 Dusehri 2.20 fgh 3.093 b 28.80 Fajri 0.45 l 1.46 i 69.18 Langra 0.73 jk 2.567 cde 71.59 Malda 1.367 i 2.533 cde 45.85 Ratul-12 0.967 j 2.70 c 64.07 Sensation 2.30 efg 3.483 a 34.71 Sindhri 1.98 h 2.617 cd 24.43 Sufaid Chaunsa 0.60 kl 1.250 i 52.0 Tukhmi 2.367 def 3.023 b 21.52 Means 1.49 2.54 Cultivar (n=12) F-value=135.1 DF= 11 Means sharing similar letters in interactional column are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
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6.3.3 POPULATION OF MANGO MEALYBUG RECORDED PER INFLORESCENCE IN TREATED AND UNTREATED TREES The results regarding population of mango mealybug per inflorescence recorded from untreated and treated trees of different cultivars reveal significant variation among population on different cultivars of mango (Table 3). The maximum population of mango mealybug was recorded to be 18, 18, 16, 16, 15, 15 and 15 per inflorescence on ‘Chaunsa’, ‘Black Chaunsa’, ‘Fajri’, ‘Malda’, ‘Ratul-12’, ‘Langra’, and ‘Sensation’, respectively. The statistically similar population of mango mealybug was recorded on ‘Sindhri’ and ‘Tukhmi’ at 12 and 12 per inflorescence followed by ‘Dusehri’ (11) and ‘Sufaid Chaunsa’ (11) whereas, minimum population was recorded on ‘Anwar Ratul’ with population of 10/ inflorescence. Table 3. MEAN COMPARISON OF THE DATA REGARDING POPULATION OF MANGO MEALYBUG RECORDED PER INFLORESCENCE IN DIFFERENT CULTIVARS OF MANGO.
Cultivars Average population /Inflorescence (**) Anwar Ratul 9.67 d Black Chaunsa 17.52 a Chaunsa 17.52 a Dusehri 11.10 cd Fajri 15.65 b Langra 15.08 b Malda 15.63 b Ratul-12 15.18 b Sensation 14.78 b Sindhri 11.75 c Sufaid Chaunsa 10.72 cd Tukhmi 11.65 c LSD @5% 1.6933 Cultivars (n=12) DF=11 F-value=22.25 Means sharing similar letters are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
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Population Initial loss final loss
20 90
18 80
16 70 14 60 12 50 10 40
Av. Population Av. 8 30 % Fruit Loss 6 20 4
2 10
0 0 Fajri Malda Langra Sindhri Tukhmi Dusehri Ratul-12 Chaunsa Sensation Varieties Ratul Anwar Black Chaunsa Black Sufaid Chaunsa Sufaid
Fig 1. INITIAL AND FINAL FRUIT LOSS IN DIFFERENT CULTIVARS OF MANGO AND POPULATION OF MANGO MEALYBUG
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6.4 DISCUSSION
The experiment was conducted to study the losses of mango fruits in different cultivars of mango caused by mango mealybug during 2006-2007 at Multan. Three gardens having all cultivars were selected. Three plants of each cultivar from each garden were kept as check and kept the pest population at zero level on 3 plants of each cultivar by development of mounds, pasting Haider’s band and application of insecticides below the bands. The data regarding population of mealybug and number of fruits per tagged inflorescence were recorded. No significant differences were found to exist among cultivars regarding number of fruits per inflorescence at initial stage of the experiment. The maximum loss in fruit yield was observed to be 11 percent in cultivar ‘Anwar Ratul’ at initial stage of the experiment followed by 11, 10, 10, 9, 9, 8 and 8 percent yield losses on ‘Ratul-12’, ‘Chaunsa’, ‘Black Chaunsa’, ‘Sindhri’, ‘Tukhmi’, ‘Dusehri’ and ‘Fajri’, respectively. The cultivars ‘Malda’, ‘Sufaid Chaunsa’, ‘Sensation’ and ‘Langra’ showed 6, 5, 5 and 3 percent yield losses, respectively at initial stage of the experiment. At final stage of the experiment ‘Chaunsa’ cultivar suffered the maximum yield loss showing 81 percent yield losses followed by 72, 69, 64, 52, 46, 35, 29, 24, 23, 22 and 18 percent yield losses on ‘Langra’, ‘Fajri’, ‘Ratul-12’, ‘Sufaid Chaunsa’, ‘Malda’, ‘Sensation’, ‘Dusehri’, ‘Sindhri’, ‘Black Chaunsa’, ‘Tukhmi’ and ‘Anwar Ratul’, respectively. It was observed that at later season, control is more critical to reduce the yield loss. It is also important to note that control measures provide a bigger benefit in cultivars that are highly susceptible to the mango mealybug. These results indicate that host plant resistance is a most important to develop and that none of the cultivars appear to exhibit tolerance to mango mealybug. However, it is notable that Black Chaunsa has high population of mango mealy bug, but still it produces high amount of mature fruits. These results indicate that mango mealybug caused losses up to 81 percent and these findings are inconformity with those of Hiepko (1983); Wodageneh (1985); Entomological Society of Nigeria (1991); Karar et al., 2007. Similarly, Moore (2004) reported that mango mealybug reduced mango yield to 50-90 percent. The present findings cannot be compared with those of Tobih (2002), because of differences in their materials and methods.
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ABSTRACT
Various cultural practices were conducted in mango orchards attacked with mango mealybug ( Drosicha mangiferae Green). The used practices were hoeing/ploughing, mounding the trunks of trees with fine mud, mounding the trunks of trees with debris, mud clods, weeds, dried leaves and rubbish material present under the tree with plastic sheet as well as without plastic sheet during the first week of April. The developed mounds were broken and spread at the end of June, July and Aug. gave significant reduction of mango mealybug population with plastic sheet i.e. 75.2 percent. Ten tree bands were tested against anscent of 1 st instar mango mealybug. Among these bands Haider’s band was found to be the most effective and lowest cost method resulting in the least percent of nymphs i.e. 1 percent crossing the band. The number of nymphs crossing the other banding methods was from 7 to 43 percent. Eleven formulations of insecticides were tested for the control of mango mealybug under laboratory as well as under field conditions. Acetamiprid was found the most effective for 1 st , 2 nd and 3 rd instars nymphs of mango mealybug at 24, 72 and 168 hrs after treatment. Supracide was the most effective for adult female at all the post treatment intervals under field conditions. A combination of mounds on the plastic sheet, Haider’s band and application of acetamiprid were found to be the most effective treatment resulted in 98 percent reduction of first instars nymphs of mango mealybug.The males of mango mealybug were attracted to mercury light and no males were attracted to yellow, green, red, blue lights. Male preferred to pupate in wet places near the ‘ kacha ’ (mud) water which can be exposed to sunlight by hoeing and can be controlled. Key words: Mango mealybug, Drosicha mangiferae, Mounds, Plastic sheet, Months, Acetamiprid, Haider’s band, Male, Light traps
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7.1 INTRODUCTION
Cultural control of insect pests consists of the regular farm operations that destroy the insects or to prevent them from causing injury to the plants. These practices are adopted by the growers’ to minimize the damage caused by insect pests (Smith et al., 1976) prior to the emergence of methods of plant sciences. Cultural practices are the broad set of management techniques or options that are utilized by agricultural producers to maximize production of crop or farm income or "the manipulation of these practices to prevent or reduce the damage of the pest" (Dhaliwal and Arora, 1998). The aim of cultural practices is to make the environment less favourable for the pest and more favourable for its natural enemies. The cultural practices are effective for the insects, which hibernate in the soil for egg laying and pupation. The most notorious pest of mango crop, the mango mealybug hibernates in the roots of host plant for egg laying. The important thing is to collect the females before egg laying, commences, by developing techniques, that are effective for collecting the females with no danger side effects (Karar and Arif, 2005). Similar the mechanical devices are also used to contol insect pest population, the use of barrier to stop the insects moving upward on the trees, collecting and destroying egg masses, hand picking of the large insects, the use of hand nets to collected insect pests, pruning and destruction of infested shoots. The mango mealybug nymphs go upward after hatching, which causes loss to mango growers. Mango mealybug is one of the most serious pests of mango and is difficult to control by insecticide. For the control of this pest non-chemical methods are better than other methods for the control of this pest (Ishaq, et al., 2004). Several workers have focused on preventing upward movement of nymphs using various bands such as grease or fluffy cotton band (Lal, 1918; Lal, 1919). Similarly, alkathane sheeting was efficacious in preventing upward movement of mealybug (Yousuf, 1993; Abrar-ul-Haq et al., 2002; Narula, 2003). Black oil cloth band was effective in preventing the upward movement of nymphs (Rahman and Latif, 1944).
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Intensive, high agricultural production systems used synthetic insecticides to eliminate insect pests traditionally as the major tool and sustain the least amount of economic damage to the crop. It may be argued critically that insecticides may be used with great care. Like Stern et.al (1959) argued, pesticides are very disruptive to the total farming, so their use should be limited to situations where the benefit (to the total crop production) outweigh the costs. The approach of preventing the population buildup by controlling egg helps to minimize the use of insecticides. Chemicals are considered the quickest method of control for different insect pests. These are important to overcome the yield reduction caused by insect pest. Although an insecticide has a number of environmental problems but still it is the widely used practice for the control of insect pest. Insecticides are the most important component of IPM program and having a number of advantages over alternate methods for the control of insect.As chemicals are easily accessible, having a wide range and are available in prepared forms in the market. A farmer can choose depending on the problem, two or more pesticides can be mixed to control the entire pest complex and insecticides can be compatible with IPM components under intensive agriculture and modern farming conditions. To save the crop from mango mealybug it may be necessary to control it through use of insecticides (Karar and Ahmad, 1999). The study was conducted to find the most effective method(s) of control and develop a sustainable management strategy by integration control of mango mealybug. The objective of the current section was collection and destruction of eggs to minimize insecticides sprays. Farmers in the past used hoeing, ploughing and digging for destroying the eggs of insects, however, it was later discouraged to avoid injuries to fibrous roots. I looked for methods to destroy the mealybug eggs without disturbing the roots systems of the plants. Further, to replace the existing practices with some new one which are easy, effective, cheap and harmless methods. In this experiment only screened practices were used which were identified through a series of experiments in mango orchards under the following objective/goals: • To promote the effective, easy, durable and inexpensive control measures for the management of mango mealybug
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• To overcome increasing problems associated with the strategy of exclusive and indiscriminate use of pesticides • To promote attractive, low-cost alternative strategies to use the local resources minimize dependence on exogenous materials • Establishment and development of a suitable IPM research application for the control of mango mealybug by considering the results obtained from the research carried out • An important aim of an IPM strategy is to integrate the available pest management options. IPM is an important component in overall crop production programme of mango
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7.2 MATERIALS AND METHODS
7.2.1 SELECTIVITY STUDIES 7.2.1.1 Cultural Control Cultural practices were conducted in those orchards (having ‘Chaunsa’ cultivar) with high infestations of mango mealybug. The egg-carrying females coming down the mango tree for egg laying were caught before spreading in the whole orchard. The data were recorded by counting the number of 1 st instar nymph from 900 cm 2 marked on trunk of tree on west side with chalk 45 cm above ground level. In the first experiment cultural practices were studied on 75 trees were selected in an orchard. There were 18 trees /treatment under 3 replications sampled for six months. In the second experiment of cultural practices were studied on 9 trees with 3 trees / treatment. The data were recorded weekly before treatment during 2005 and then after treatment during 2006 and 2007 from the same orchard by counting the number of 1 st instar present in the area of 900 cm 2 on the same month and date. The data were compiled and analyzed through Complete Randomized Design. The percent reduction of nymphs was calculated through the formula Percent reduction = Av. pop. recorded in control 900 cm 2 − Av. pop. recorded in treatme nt 900 cm 2 × 100 Av. population recorded in control 900 cm 2 The treatments for the cultural practices are listed below. 7.2.1.1.1 Hoeing/Ploughing The orchard was ploughed with a cultivator once in the month of June. After ploughing, 3 trees were hoed in each month around the trunk of trees within the radius of one meter by using spade started from June, 2005 till Nov., 2005. So the 18 trees were hoed in six months and the data was recorded in Dec., 2005 to Feb., 2006. 7.2.1.1.2 Earthing/Mounding the tree trunk with fine soil The trunks of 18 trees were mounded with fine mud at the height of 45 cm in the 1st week of Apr. 2005 to collect the gravid females. For direct falling females as well as
115 Chapter 7 Sustainable Management of Mango Mealybug those females that were wandering for hibernation four other mounds were made under the tree with the same fine mud having 30 x 30 cm (height and width) in four different directions such as east, west, north and south away from 182 cm of tree. One tree had 5 mounds. The mounds of three trees were spread (15 mounds) in each month starting from June, 2005 to Nov., 2005. 7.2.1.1.3 Earthing/Mounding the tree trunk with clods, fallen leaves and debris The trunks of 18 trees were mounded with the material found under the tree i.e. dried and fallen leaves, weeds ,clods of mud, grass, debris and small dried branches up to 45 cm high in the 1st week of Apr., 2005 to collect the egg carrying females. For direct falling females as well as those females which are wandering for hibernation four other mounds of 30 x 30 cm (height and width) were made under the tree with the same materials in four different directions east, west, north and south away from 182 cm of tree. One tree had 5 mounds. The mounds of three trees were spread (15 mounds) in each month starting from June, 2005 to Nov., 2005. 7.2.1.1.4 Mounds of clods, fallen leaves and debris on plastic sheet A plastic sheet of 150 cm in width was spread on the ground around the trunk of each tree. On the sheet, 18 mounds were prepared around the trunk of trees with the material found under the tree i.e. with clods, fallen leaves, debris and small dried branches up to 45 cm high in the 1st week of Apr. 2005 to collect the egg carrying females. For direct falling females as well as those females which are wandering for hibernation four other mounds of 30 x 30 cm (height and width) were made under the tree with the same materials in four different directions east, west, north and south away from 182 cm of tree. One tree had 5 mounds. The mounds of three trees were spread (15 mounds) in each month starting from June, 2005 to Nov., 2005. 7.2.1.1.5 Removal of soil from the orchard Heavily infested soils with the eggs of mango mealybug were removed around the trunk of 3 trees in the month of Nov., 2005 before hatching of eggs up to 5 to 7 cm. The data were taken three selected trees in the month of Dec., 2005 to Feb., 2006. 7.2.1.1.6 Intercropping The field was irrigated and then 3-4 ploughings were done in the orchard before sowing of fodder. On the 22 nd Sept., 2005, oat (Avena sativa L.) was sown as a fodder
116 Chapter 7 Sustainable Management of Mango Mealybug and then on 2nd of Oct., 2005, berseem clover (Trifolium alexandrinum L.) was spread after irrigation. The data were taken from three selected trees in the month of Dec., 2005 to Feb., 2006 7.2.1.1.7 Unploughed orchard Three trees were kept as control where no practice was applied throughout the season. 7.2.1.2 Mechanical control Ten different bands were installed once in the first week of Dec., 2005 around the trunk of tree 60 cm above the ground level before the hatching of eggs. A common band (grease band) was installed on each of these tested bands at the height of 25 cm. So that the nymph crossed the tested bands were gathered below the upper band were counted weekly. The grease bands were repaired every week after recording the data. Average population was counted from the area of 6.5 cm 2 between two bands as well as below bands. The data were compiled and analyzed as Completely Randomized Design. The percent of the population crossing the band was calculated through the formula; Av. population crossed the band 6.45 cm 2- Formula= × 100 Av.populat ion below the band 6.45 cm 2- After counting the number of mealybugs between two bands, the space between the bands were sprayed with Acetamiprid @1g/1 liters of water with the help of small hand operated sprayer (automizer) weekly. The following bands were used for comparison. BANDS WIDTH 1-Namhar band 7.6 cm 2-Black oil cloth band 7.6 cm 3-Gunny bag band 25.4 cm 4-Greeze band 7.6 cm 5-Greeze mixes with black oil 7.6 cm 6-Funnel Type Trape 30.5 cm 7-Cotton band 7.6 cm 8- Polyethelene sheet band 22.9 cm 9-Plastic sheet band 22.9 cm 10-Haider’s Band 22.9 cm + 3.8 cm grease in middle
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The details of different bands are given below. DESCRIPTION OF BANDS 1- NAMHAR BAND. Materials Required Quantity Part A Castor oil 454 g
Conc.H 2SO 4 227 g Part B Rosin 1362 g Axle Grease 908 g Glycerin 2 oz Unslaked lime 5-10 g Preparation Part A
For the preparation of this band H 2SO 4 was mixed in castor oil in a plastic container and kept them for 15 days. Part B After 15 days, rosin was heated in a steel container on fire until it becomes thin like water. In this heated rosin, grease was added and continuously stirs until it mixes completely. It was removed from the fire and glycerin was added. The whole mixture was stirred well with a stick and allowed them to cool. After cooling mixture B was poured in to mixture A and stir continuously with a wooden stick until both the mixtures mixed completely. This mixture was named as Namhar band. Effectiveness It was effective up to 4-5 weeks after application. With the passage of timely it loosed its efficacy slowly and the nymph crosses this band easily. Limitation • With rain water it becomes hard, which affects its efficiency. • Take long time for preparation • Very technical
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• Most laborious • Costly 2-BLACK OIL CLOTH BAND Material Required • Crude cloth of cotton having 7.6 cm width and length according to tree trunk. • Used oil of vehicle • Nails 2-3 of 2.5 cm and • Hammer Preparation The cloth was dipped in the black oil for 5-10 minutes until it absorbed the oil completely. Take the cloth was taken out and wrapped on the tree trunk tightly with 2-3 nails of 2.5 cm. Effectiveness • Low number of nymphs crossed it. • Rain affected its efficacy Limitation • Not observed 3-GUNNY BAGS Material Required • Gunny bag • Scissor • Nails 2-3 of 2.5 cm and • Hammer Preparation Cut piece of bag having 25.4 cm in width with the help of scissor. It was wrapped on the tree trunk with 3 nails. Effectiveness • The nymphs passed easily through the holes of the gunny bags as well as crossed the bag and went up the tree. • No effect of rainfall.
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Limitation • Squirrels damaged the bag and took them for their nest preparation. 4-GREAZE BAND Material Required • Grease • Spatula Preparation Axle grease and was smeared on the trunk of tree with spatula in the form of ring of 7.6 cm in width. Effectiveness It was effective 1-2 weeks after application. After this period the nymphs crossed this band. A large number of nymphs was gathered below this band and can easily be killed with help of insecticides. Limitation Grease treated places on the trees trunks were either shrunk or busted. From the busted bark the gum came out and the trunks become weak. The width of the trunk was reduced about 1.3 to 2.5 cm on the treated portion. Rainfall hardens the grease and nymphs easily crossed it. Sometimes a bridge of dead nymphs formed on this band for crossing the remaining nymph.
5- GREASE MIXED WITH BLACK OIL Material required • Grease • Black oil • Spatula Preparatio n An equal amount of grease and black oil were mixed i.e. 1:1 in a plastic container. It was pasted on the trunk of tree with spatula in the form of ring of 7.62 cm.
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Limitation • The bark of trunk treated with this mixture was either shrunk or thickened and then busted. Gum oozed from the busted bark gums and the tree was weaken. The width of the trunk was reduced at about 1.3 to 2.5 cm on the treated portion. • Rainfall hardens the band allowing nymphs to easily cross due to its hardness. A bridge of dead nymphs formed on the band and facilitated the crossing of the remaining nymph. 6-FUNNAL TYPE TRAP Material Required • Polyethylene plastic of 12 inch width • Soft steel wire • Nails • Hammer • Calcium carbonate Preparation • The polyethylene sheeting was used for the preparation of the band and bend 1.3 cm from the upper side. The wire is passed from this bent portion and was tight together in the form of ring around the trunk of trees. It was fixed on the trunk of tree with the help of nails from the lower sides and the upper sides remain open like funnel. Effectiveness • Less number of nymphs crossed this trap. • The egg carrying females were collected in the funnel when they came downward. Limitation • Rainfall seriously affects. The rain water gathered in this funnal. There is no way for the water to go out and ruins the funnel. • Costly • Highly technical • Laborious • Not suitable for all types of trunk. • Very difficult to install.
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7-COTTON BAND (FLUFFY BAND) Material Required • Cotton lint • Rope • Nails Preparation • Lint was purchased from the market. A nail was fixed with hammer on the trunk 60 cm above ground level. One end of the rope was tied on the nail and put the lint under the rope with a width of 7.6 cm and again tied it with nail. In this way lint is wrapped around the trunk. Limitation • Nymph easily crossed the lint. • Rainfall compact the lint which allow more nymph to cross. • New lint was wrapped after every rainfall. • Squirrels take this for their nest preparation 8- POLYETHYLENE SHEET BAND Material Required • Polyethylene sheet of 22.9 cm width • Nails 2-3 and • Hammer Preparation • A mixture of mud and manure was prepared with a ratio of 1:1 and were pasted on the trunk of trees in the form of ring to fill the cracks. On this ring, a polyethylene sheet of 22.9 cm was wrapped with 3 nails (above, below and middle). Effectiveness • Some nymphs crossed this plastic sheet and climbed up the tree. • No effect of rainfall. Limitation • Not observe
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9- PLASTIC SHEET BAND: Material Required • Common plastic of width 22.9 cm • Nails 2-3 of 2.5 cm and • Hammer Preparation • A mixture of mud and manure was prepared with a ratio of 1:1 and were pasted on the trunk of trees in the form of ring to fill the cracks. On this ring, a plastic sheet was wrapped with 3 nails (above, below and middle). Effectiveness • Nymph crossed this type of plastic sheet. • No effect of rainfall. Limitation Not observed 10- HAIDER’S BAND. Material Required • Common plastic sheet of 22.86 cm width • Grease • Black oil • Spatula • Nails 2-3 of 2.54 cm and • Hammer Preparation It consisted on a plastic sheet and 3.81 cm grease. The trunk of the tree is firstly plastered with mixture of mud and wet farm yard manure at the ratio of 1:1. It is pasted all around the trunk 25.4 cm in width from 60 cm above the ground so that it provides an even and smooth surface for wrapping the plastic sheet which does not allow the nymphs to crawl from underneath the band. Then plastic sheeting is wrapped around the trunk on the surface pasted with mud mixture. The plastic sheet is tightened from the joining ends with 3 small 1.27 cm iron nails (upper, middle, lower ends of joint) with the help of hammer. After fully wrapping the plastic sheet a 3.81 cm grease band is applied in the
123 Chapter 7 Sustainable Management of Mango Mealybug middle portion of plastic sheet. It forms a band which has been named as Haider’s band. This is new addition in mechanical control of mango mealybug. It was applied on the trunk of trees in Dec., 2006 untill the 3rd week of Feb., 2007 to stop the upward movement of nymphs. Effectiveness • Very effective barrier against crawling insects. It remains effective throughout the season even up to one year and is very cheap. In sunshine the grease becomes thin and remains effective for several months. • Rainfall did not effect its functioning. No bad effects were seen on the trees trunk, as the grease did not touch the trunk directly. • The grease was not dried on plastic sheet. Limitation • Not observed 7.2.1.3 Chemical control 7.2.1.3.1 Control of mango mealybug under laboratory conditions The experiment was conducted in the laboratory at Agriculture College laboratory, Department of Agri. Entomology, Baha-ud-Zakariya University, Multan. The 1st instars nymphs of the mango mealybug, Drosicha mangiferae (Green) were collected from an infested commercial mango orchard in Multan during Jan., 2006. Test solutions were prepared by mixing the concentrations of different insecticides in 30 ml water in a beaker. Leaf discs of 5 cm diameter were cut from nonsprayed mango leaves, which were washed and dried before cutting. These leaf discs were dipped in test solutions for 10 seconds with gentle agitation and then were placed on tissue paper for drying, with the adaxial surface facing up. After drying, they were placed in 5 cm plastic petri dishes that contained moist filter paper at their bottoms, to avoid desiccations. Forty 1 st instars nymphs were released on each leaf disc present in Petri dish. Each treatment was replicated thrice, including the controls. Mortality was assessed after 24, 48, 72, 96, 120, 144 and 168 hours of exposure to insecticide. Nymphs that failed to show movement after a gentle touch with needle were considered to be dead. Each insecticides formulations had 3 different doses i.e. one treatment below the recommended dose, 2 nd recommended dose and 3 rd above recommended dose. Among the treatments:
124 Chapter 7 Sustainable Management of Mango Mealybug profenophos (Curacron) 500EC @ 30-ml a.i. 15-g (500g/l profenophos, Ciba-Geigy Pak.Ltd., Basel, Switzerland), bifenthrin (Talstar) 10EC @ 100-ml a.i. 10-g (10 percent bifenthrin, FMC United, pvt., Ltd., USA), triazophos (Hostathion) 20EC @ 100-ml a.i. 20g (20 percent triazophos, Bayer Crop Science, France), chlorpyrifos (Lorsban) 40EC @ 50-ml a.i. 20-g (40 percent chlorpyrifos, BASF Chemicals & Polymers Pakistan (Pvt.) Ltd., Germany), lambdacyhalothrin (Karate) 2.5EC @ 50-ml a.i. 1.25-g (2.5 percent lambdacyhalothrin, Ciba-Geigy Pak.Ltd., Basel, Switzerland), imidacloprid (Confidor) 200SL @ 100g a.i. 20-g ( 200SL & 94 percent Techanical imidacloprid, Bayer Crop Science, France), buprofezin (Starter) @ 500-g a.i. 125-g (25 percent WP & 95 percent Tech., Pak.China Ltd.), deltamethrin (Decis) 2.5EC @ 50-ml a.i. 1.25g (2.5 percent deltamethrin, Bayer Crop Science, France), cypermethrin (Ripcord) 10EC @ 100-ml a.i. 10-g (10 percent cypermethrin, Swat Agro Chemicals, Germany), acetamiprid (Mospilan) 20SP @ 100-g a.i. 20-g (20 percent acetamiprid, Nippon Soda Co. Ltd ., Tokyo, Japan), methidathion (Supracide) 40EC@150-ml a.i. 60-g (40 percent methidathion, Ciba-Geigy Pak.Ltd., Basel, Switzerland ) (Tomlin, 1997) at the indicated dose gave 100 percent mortality after 168 hours post treatment.The percent mortality was calculated and analyzed as a Completely Randomized Design. 7.2.1.3.2 Control of mango mealybug under field conditions The formulations of following insecticides i.e. profenohpos, bifenthrin, triazophos, chlorpyrifos, lambdacyhalothrin, imidacloprid, buprofezin, deltamethrin, cypermethrin, acetamiprid and methidathion were sprayed in the field on mango trees against 1 st instar nymphs of mango mealybug in the month of Feb., 2006 and the same dose of insecticides were sprayed against 2 nd & 3 rd instar in the month of Mar., 2006 and against adult female in the month of Apr., 2006. The two branches of 30 cm in length on mango trees were selected, tagged and the population of nymphs were counted from these branches including leaves, twig and inflorescence. The data were recorded before spray and then 24 h, 72 h and 168 h after spray. On the soil below each of the selected branches a square meter soil was levelled and cleaned. The number of nymphs falling out of the tree and onto the ground was also checked regularly for their mortality from this square meter. The ‘Black Chaunsa’ cultivar of mango was selected for chemical control. Calibration was done before the spray for measuring the quantity of water used for each
125 Chapter 7 Sustainable Management of Mango Mealybug treatment. Each tree was labelled with iron sheet fixed with nails and hammer. The date of spray, treatment and replication were written on iron sheet. The trees were sprayed with hand knapsack sprayer. The data was compiled and percent mortality was calculated through formula Population recorded before spray − Population recorded after spray % Mortality = × 100 Population recorded before spray The data were analyzed as a Completely Randomized Design on an IBM-PC Computer using M. Stat (Steel and Torrie, 1980) Package. Means were separated by Duncan’s New Multiple Range Test (DMRT) (Duncan, 1955). 7.2.2 Sustainable management of mango mealybug The experiment was designed based on preliminary data, which was obtained in 2006. An orchard, having commercial mango cultivar ‘Chaunsa’ (‘Sammar Bahist’) heavily infested with mango mealybug was selected. A Complete Randomized Design with 8 treatments including 1 control was used and each treatment had three replications. The effect of management strategies were observed by counting the population of the 1 st instars weekly from the trunk of trees in 900 cm 2 area, marked on the trunk with chalk 45 cm above the ground. Marked portion was repaired weekly after data collection. The percent reduction in population was calculated using the formula Av. pop. 900 cm -2 in control - Av. pop. 900 cm -2 in treatme nts Percent reduction = Av. pop. 900 cm 2- in control
7.2.2.1 Cultural practices Cultural practices were done to collect the egg-carrying females in mounds before the insect spreading to different places for hibernation and egg laying. To collect mealybugs, a plastic sheet of 152 cm in width and length according to tree trunk was spread around the tree trunk. Mounds were made on the plastic sheet around the trunk with the materials present under the tree like dried leaves, weeds, clods of mud, grass, debris and small dried branches up to 45 cm high in the 1 st week of Apr., 2007. For direct falling females as well as those females which were searching for hibernation sites four other mounds of 30 x 30 cm were made under the tree with the same materials in four different directions east, west, north and south away from 180 cm of tree trunk without
126 Chapter 7 Sustainable Management of Mango Mealybug plastic sheet (5 mounds/tree). These mounds were spread at the end of June, 2007 after hibernation and egg laying of females.
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7.2.2.2 Mechanical practices In this practice, a band was designed and named as Haider’s band was used. The band was made of a plastic sheet and 3.81 cm layer of grease. The trunk of the tree was first plastered with mixture of mud and wet farmyard manure at the ratio of 1:1. It was pasted around the trunk at 25 cm width from 45 cm above the ground. The plastic sheet was then wrapped around the trunk on mud pasted. It was tightened at the corners with 3 small 1.27 cm iron nails (upper, middle, lower ends of joint). After wrapping the plastic sheet, 3.81 cm grease band was applied in the middle portion of plastic sheet. 7.2.2.3 Chemical practices Trees infested with first instars were sprayed once with Acetamiprid at 100g/100 liter of water using hand knapsack sprayer. The spray was carried out on three selected trees. 7.2.2.4 Mechanical x chemical practice Haiders bands were applied on the trunk of 3 trees in Dec., 2006 to 3 rd week of Feb., 2007 to stop the upward movements of 1 st instar nymphs. The nymphs that gathered below the band were sprayed once with insecticide Acetamiprid @ 1g / liter (formulated insecticide) of water in the 2 nd week of Feb. 7.2.2.5 Cultural x mechanical practice A plastic sheet of 152 cm in width and length according to the size of trunk were spread around the trunk of three trees to stop the entry of females in to roots of host plant. Mounds were made on the plastic sheet around the trunk of three trees with the materials present under the tree like dried and fallen leaves, weeds, clods of mud, grass, debris and small dried branches up to 45 cm high in the 1st week of Apr., 2006. For direct falling females as well as those females which were searching their hibernation places four other mounds of 30 x 30 cm were made under the tree with the same materials in four different directions such as east, west, north and south away from 180 cm of tree trunk without plastic sheet (5 mounds/ tree). These mounds were spread at the end of June, 2006 after hibernation and egg laying of females. Haider’s band was applied on the trunk of these trees to stop the nymphs below the band in Dec., 2006 to 3 rd week of Feb., 2007.
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7.2.2.6 Cultural x chemical practice Mounds were made on the plastic sheet around the trunk of three trees in the 1 st week of Apr., 2006 and these mounds were spread at the end of June, 2006. These trees were sprayed thoroughly once with Acetamiprid @ 100g/100 liter (formulation) of water against 1 st instar in the 2 nd week of Feb., 2007. 7.2.2.7 Cultural x mechanical x chemical practices Mounds were made on the plastic sheet around the trunk of three trees in the 1 st week of Apr., 2006 and these mounds were spread at the end of June, 2006. Haider’s band was applied in the month of Dec., 2006. The nymphs gathered below the band were sprayed once with chemical Acetamiprid @ 1 g/ liter (formulated insecticide) of water in the 2 nd week of Feb. 7.2.2.8 Control Three trees were kept as control where no practice was applied throughout the season. 7.2.3 MANAGEMENT OF MANGO MEALYBUG MALES 7.2.3.1 Management through Light traps Lights of different colors like yellow, red, mercury, blue and green bulb of 100 watts were used in traps during peak activity of males. These traps were installed for 8 days in the mango orchard started on 13.4.07 till to 20.04.07. Count of males were made daily and removed from the traps. The data were analyzed through Completely Randomized Design. 7.2.3.2 Management through cultural practices Pupae of mango mealybug males were exposed from different places by hoeing. The number of pupae exposed, were counted from 900 cm 2 (three times from one place) at 6 different places were taken to know the preferred places of its hibernation. The following places were hoed up to 5 cm depth i.e. under the tree near trunk (Semi-wet soil), under the tree near trunk (Dry soil), near mud water channel (Semi-wet soil), under leaves (Semi-wet soil), under leaves (Dry soil) and on tree trunk bark. These selected places were hoed with ‘ ramba’ (A steel instrument used for hoeing purposes) and counted the exposed pupae. After 10 days again these places were visited and observed exposed pupae for the emergence of males. The data were analyzed as a Completely Randomized Design. LSD test were used to measure the variability.
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7.3 RESULTS AND DISCUSSION
7.3.1 CULTURAL METHODS FOR THE CONTROL OF MANGO MEALYBUG Experiment 1 Various cultural practices such as hoeing/ploughing (T1), earthing/mounding the tree trunk with fine mud (T2), earthing/mounding the trees trunk with the material present under the tree like dried leave, branches, weeds, debris and mud clods (T3), mounding the trunk with dried material present under the tree like leaves, branches, weeds, debris and mud clods after spreading plastic sheet (T4) and nonploughed orchard as control were applied in highly infested trees of mango during different months of the year for the collection of egg carrying females coming down the trees for egg laying as well as for the destruction of eggs. The practices were applied during, 2005 and 2006. The data on first instar nymphs of mango mealybug were recorded from the trunk of the trees and percent reduction over control was calculated. The data regarding percent reduction in various treatments over control based on the number of alive mango mealybug per 900 cm 2 of mango mealybug on the trunk in different treatments applied during various months from June, 2005 to Nov., 2005 are given in (Table 1). The data reveal significant variation (P < 0 .01) between years, among treatments, months of application and in their all interactions. The means were compared by DMR Test at P=0.05. The results reveal that T4 was found to be the most effective treatment resulted in maximum reduction i.e. 75 percent followed by T3 with 71 percent reduction of first instars nymph. T2 did not show good control of first instars nymphs of mango mealybug showing minimum reduction i.e. 27 percent and differed significantly from those of observed in all other treatments. The treatment T1 resulted in 42 percent reduction and was found as intermediate with significant difference from other treatments.
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Table 1. MEAN COMPARISON OF THE DATA REGARDING REDUCTION IN PERCENTAGE OF NYMPHS OF MANGO MEALYBUG IN DIFFERENT TREATMENTS AND MONTHS OF THE YEAR DURING 2006 AND 2007. Treatments x year (**) LSD= 0.65 Treatments Percent reduction of insect during Means (**) 2006 2007 LSD= 0.46 T-1 37.83 f 46.13 e 41.98 c T-2 23.59 h 29.79 g 26.69 d T-3 65.77 d 75.43 b 70.60 b T-4 71.55 c 78.80 a 75.18 a Control 0.00 i 0.00 i 0.00 e Means 39.75 a 46.03 b F-value 128.2 35878.5 D.F=4 Means sharing similar letters are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01. Where as T-1= Hoeing/ploughing T-2= Mounding/ earthing the trees with fine mud T-3= Mounding /earthing the trees with debris, dried leaves, small branches, clods of mud T-4= Mounding/ earthing the trees on the plastic sheet with debris, dried leaves, small branches, clods of mud. Control = No practice applied
It is evident from the results that the treatments applied during the month of June (Table 2) resulted in maximum reduction in the population of mango mealybug i.e. 48 percent followed by 46 and 45 percent where the treatments were applied during the month of July and Aug. respectively and differed significantly with one another. The treatments applied during the month of Nov. showed minimum reduction i.e. 32 percent followed by 42 and 43 percent where treatments were applied during the months of Sept. and Oct. respectively. From these results it is concluded that cultural practices should be applied during the month of June for maximum control of mango mealybug. The application of mounding around the trunk with fine mud applied during all the months did not show significant difference showing 23 to 26 percent reduction of
131 Chapter 7 Sustainable Management of Mango Mealybug mango mealybug except this treatment when applied during the month of Oct. showed significantly maximum reduction i.e. 35 percent. All the treatments showed maximum reduction of mango mealybug applied during the month of June except T2 where the trunk was mounded with fine mud. The percent reduction of mango mealybug decreased in almost all the treatments applied after June.
Table 2. MEAN COMPARISON OF THE DATA REGARDING REDUCTION IN PERCENTAGE OF NYMPHS OF MANGO MEALYBUG IN DIFFERENT TREATMENTS AND MONTHS OF THE YEAR DURING 2006 AND 2007.
Treatments x Month (**) Months (**) Month LSD=1.13 Means T1 T2 T3 T4 Control LSD=0.51 June 54.42 i 26.15 o 78.31 c 81.83 a 0.00 r 48.14 a July 50.13 j 23.07 o 77.02 d 81.62 a 0.00 r 46.37 b Aug. 45.83 k 26.28 o 75.73 e 79.45 b 0.00 r 45.46 c Sept. 37.51 m 23.27 o 72.69 f 75.39 e 0.00 r 41.77 e Oct. 39.17 l 35.17 n 68.84 g 72.71 f 0.00 r 43.18 d Nov. 24.81 p 26.22 o 51.03 j 60.07 h 0.00 r 32.43 f LSD=0.46 41.98 c 26.69 d 70.60 b 75.18 a 0.00 e D.F= 20 F.value=222.0 D.F= 5 F.value=960.2 Means sharing similar letters are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01. Where as T-1= Hoeing/ploughing T-2= Mounding/ earthing the trees with fine mud T-3= Mounding /earthing the trees with debris, dried leaves, small branches, clods of mud T-4= Mounding/ earthing the trees on the plastic sheet with debris, dried leaves, small branches, clods of mud. Control= No practice applied
Experiment 2 Two treatments viz., removal of soil around the trunk of selected trees in the month of Nov. and intercropping of Oat and Berseem clover as fodder grown as intercrop
132 Chapter 7 Sustainable Management of Mango Mealybug on Sept. 22, 2005 and Oct. 2, 2005, respectively along with a control (nonploughed orchard) were tested for the control of mango mealybug. The results regarding emergence of first nymphal instar climbing up of the tree trunk were recorded and percent reduction over control was calculated. The comparison of means are presented in Table 3 and reveal highly significant differences between treatments, years as well as in the interactions of treatment and year. The maximum reduction was recorded to be 77 percent in those trees where Oat and Berseem clover were intercropped, while minimum was observed in those trees where the soil was ploughed and removed showing 64 percent reduction of mango mealybug. The results obtained from the interaction response of both the treatments reveal that the application of these cultural practices showed minimum reduction of mango mealybug during 2006 as compared to 2007 in both the treatments. Intercropping trees showed maximum reduction, whereas removal of soil resulted in minimum reduction in both the study years. From these results it is suggested that good results regarding the control of mango mealybug can be achieved if these practices specially intercropping may be done continuously and regularly. Table 3. MEAN COMPARISON OF THE DATA REGARDING PERCENT REDUCTION OF FIRST INSTARS NYMPHS OF MANGO MEALYBUGIN DIFFERENT TREATMENTS DURING 2006 AND 2007.
Treatments x Year (**) Practices LSD =0.424 Treatment Means(**) 2006 2007 LSD=0.300 Intercropping 68.36 c 84.86 a 76.61 a Removal of Soil 54.37 d 73.91 b 64.14 b Control 0.00 e 0.00 e 0.00 c Year 61.37 b 79.39 a D.F= 2 F-value= 2901.6 D.F=2 F-value= 177428.6 Means sharing similar letters are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
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7.3.2 MECHANICAL METHODS OF CONTROL Various mechanical methods in the form of bands viz., namhar band, black oil cloth band, gunny bag, grease band, grease + black oil, funnel type trap, cotton band, polyethylene sheet, plastic sheet and Haider’s band were applied for the control of mango mealybug for two years viz., 2005-06 and 2006-07. On each tested band, a common band of grease was applied to count the population of crossed nymphs. The bands were applied during Dec., 2005. The observations regarding number of 1 st instar mango mealybug nymphs crossed the tested band on the tree trunk gathered below the upper band were counted at one week interval started from Jan. 7, 2006 to Feb. 19, 2006 of each year with little variation. Bands were again applied during Dec., 2006 and the data were recorded from Jan. 7, 2007 to Feb. 19, 2007. The results are presented under the following sub- sections. 7.3.2.1 Effect of Bands on the Nymphs of Mango Mealybug During 2006 The data regarding the effectiveness of various bands used to stop the upward movement of the nymphs of mango mealybug at various dates of observation during 2006 are given in (Table 4). The means comparisons of the same reveal highly significant difference among treatments and dates of observation. The means were compared by DMR Test at 0.05. Haider’s band was found to be the most effective and resulted in the lowest population of mango mealybug nymphs crossing the band (1 percent) and differed significantly from those of observed in all other mechanical bands. The application of plastic sheet, polyethylene sheet and funnel type traps were found to be less effective with 10, 10 and 8 percent nymphs of mango mealybug crossed the bands, respectively, and did not differ significantly with each other. Black oil cloth band also showed significant effect regarding stopping the upward movement of mango mealybug nymphs, resulted in 14 percent individuals crossed the bands and showed significant variation from those of found in all other treatments. Gunny bag and cotton band were not so effective resulting in 45 and 43 percent nymphs of mango mealybug crossing the bands on the tree trunk and did not show significant variation with one another. Similarly namhar band, grease band and grease + black oil band showed 34, 38 and 30 percent nymphs crossed the band installed on the tree trunk, respectively which did not prove so
134 Chapter 7 Sustainable Management of Mango Mealybug effective and differed significantly from each other. From these results it was observed that Haider’s band was found to be the most effective regarding stopping the upward movement of mango mealybug nymphs followed by funnel type trap, polyethylene and plastic sheet. Similarly, the results based on interaction between the effects of different bands at various dates of observation also showed similar trend in controlling the mango mealybug. Haider’s band resulted in significantly the lowest population of the pest crossed the band at all the dates of observation compared with results of other bands. Cotton wool band and gunny bag showed comparatively higher population of mango mealybug at all the dates of observation and proved inferior. Table 4. MEAN COMPARISON OF THE DATA REGARDING PERCENT POPULATION CROSS THE TESTING BAND DURING 2006.
Treatments Dates x Treatment (**) Treatment LSD=5.91 Means(**) 07.01.06 14.01.06 21.01.06 28.01.06 04.02.06 13.02.06 19.02.06 LSD =2.23 A B C D E F G H Namhar Band 0.00 t 2.42 rst 21.37 41.57 49.91 fg 49.94 de 60.25 de 33.63 c mn hij Black Oil 0.00 t 4.25 rst 9.21 qr 11.71 pq 14.83 26.12 m 33.04 l 14.16 e Cloth nopq Gunny Bag 0.63 t 16.62 35.77 47.34 gh 58.75 de 78.09 ab 75.57 bc 44.68 a nop jkl Grease Band 0.00 t 3.71 rst 35.19 46.70 gh 49.56 fg 64.89 d 64.61 d 37.81 b jkl Grease+Black 0.00 t 2.81 rst 25.05 m 36.80 42.35 hi 47.55 gh 54.91 ef 29.92 d Oil ijkl Funnel Type 0.00 t 1.19 t 3.13 rst 8.86 qrs 12.65 pq 13.99 14.16 7.71 f Trap opq opq Cotton Wool 1.15 t 14.33 40.11 34.43 kl 59.09 de 83.88 a 71.34 c 43.48 a Band opq ijk Polyethylene 0.00 t 1.65 t 4.38 rst 8.91 qrs 14.87 15.35 20.60 9.39 f Sheet Band nopq nopq mno Plastic Sheet 0.00 t 1.93 st 4.13 rst 9.17 qr 16.91 17.42 17.58 9.59 f Band nop nop nop Haider’s 0.00 t 0.00 t 0.78 t 0.94 t 1.11 t 1.31 t 1.52 t 0.81 g Band LSD =1.8689 0.18 f 4.89 e 17.91 d 24.64 c 32.00 b 40.85 a 41.36 a Df=54 F-value= 29.7 Df=9 F- value=424.6 Bands (n=10) Means sharing similar letters in columns A to G for interaction and in column H for treatment means did not differ significantly by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
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7.3.2.2 Effect of Bands on the Nymphs of Mango Mealybug During 2007 The data relating to the effectiveness of various bands on the nymphs of mango mealybug at various dates of observations during 2007 are given in Table 5. The means comparisons of the same reveal highly significant difference between treatments and dates of observation. The means were compared by DMR Test at P=0.05 (Table 4). It is evident from the results that Haider’s bands again proved to be the most effective resulted in the lowest percentage of mango mealybug crossed the band applied on tree trunk i.e. 0.41 and differed significantly from those of observed in all other treatments. The application of polyethylene sheet and plastic sheet bands were found to be the next effective resulted in 8 and 9 percent nymphs crossed the band and did not differ significantly from each other. The application of cotton bands did not prove effective against the mango mealybug resulted in maximum number of individual crossed the tree trunk i.e. 43 percent and differed significantly from those of recorded in all other treatments. The Funnal type trap also showed significant control of mango mealybug nymphs with 7 percent individuals crossed the band and also showed significant differences from those of observed in all other treatments. The application of cotton band, grease band, namhar band, grease + black oil band and black oil cloth band resulted in 38, 29, 28, 23 and 14 percent individual crossed the tree trunk, respectively and differed significantly from one another. These bands were ranked as intermediate. The results regarding the effect of different bands on the population of mango mealybug at various dates of observation reveal that Haider’s band showed significant control of the pest resulted in the lowest population crossed the bands at all the dates of observation. The dates of observation effects were non-significant for Haider’s band. On the other hand, cotton wool band found less effective resulted in maximum population crossed the band at almost all the dates of observation as compared to other treatments. Haider’s band again proved an effective barrier for the ascent nymphs of mango mealybug.
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Table 5. MEAN COMPARISON OF THE DATA REGARDING PERCENT POPULATION CROSS THE TESTING BAND DURING 2007. Dates x Treatments (**) Treatment LSD=2.0929 Means(**) Treatments LSD 07.01.07 14.01.07 21.01.07 28.01.07 04.02.07 13.02.07 19.02.07 =0.7910 A B C D E F G H Namhar Band 0.00 ^ 2.20 19.58 q 42.49 ij 48.26 f 43.69 41.59 j 28.26 c z[/]^ hij Black Oil 0.00 ^ 3.12 z[ 9.07 y 13.35 15.54 rst 20.49 q 26.37 o 12.42 e Cloth uvw Gunny Bag 0.81 [/]^ 16.01 rs 36.30 kl 47.81 fg 57.29 c 55.02 d 49.65 ef 37.56 b Grease Band 0.00 ^ 2.68 z[/] 30.57 36.48 kl 42.90 ij 44.03 hi 45.80 gh 28.92 c mn Grease+Black 0.00 ^ 2.37 23.29 p 30.01 n 37.62 k 36.17 kl 32.37 m 23.12 d Oil z[/]^ Funnel Type 0.00 ^ 0.90 [/]^ 2.91 z[/ 9.46 xy 13.37 12.43 9.26 xy 6.90 g Trap tuvw uvw Cotton Wool 0.89 [/]^ 12.91 34.91 l 50.48 e 58.47 c 71.76 a 69.61 b 42.72 a Band uvw Polyethylene 0.00 ^ 1.42 3.67 z 12.16 13.80 16.33 r 11.09 8.35 f Sheet Band z[/]^ uvw stuv wxy Plastic Sheet 0.00 ^ 1.55 3.79 z 11.50 16.19 r 16.37 r 14.28 9.09 f Band z[/]^ vwx rstu Haider’s 0.00 ^ 0.00 ^ 0.31 ]^ 0.79 [/]^ 0.88 [/]^ 0.56 /]^ 0.29 ]^ 0.41 h Band LSD =0.6618 0.17 f 4.32 e 16.44 d 25.35 c 30.43 b 31.68 a 30.03 b Df=54 F-value= 154.8 Df= 9 F- value=2566.4 Bands (n=10) Means sharing similar letters in columns A to G for interaction and in column H for treatment means did not differ significantly by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
7.3.2.3 Average Effect of Bands on the Nymphs of Mango Mealybug During 2006 and 2007 The results regarding the effectiveness of different bands applied on tree trunk were analyzed cumulatively to determine the average effect of both the study years viz., 2006 and 2007 for the control of mango mealybug (Table 6). Significant differences were found to exist between years, among dates of observation and treatments. The means comparison of the results showed that Haider’s bands was proved to be the most effective resulted in the lowest number of nymphs (0.6 percent) crossed the band applied on the tree trunk and differed significantly from those of observed in all other treatments. Funnel type trap was found to be a next effective band with 7 percent nymphs crossed the band and also showed significant difference from those of found in all other treatments. No significant difference was found to exist between polyethylene sheet and plastic sheet
137 Chapter 7 Sustainable Management of Mango Mealybug bands with 9 and 9 percent nymphs crossed the band, respectively. The application of cotton bands was not an effective treatment and resulted in the highest percentage of nymphs crossing the band (43 percent) followed by 41, 33, 31, 27 and 14 percent in those treatments where gunny bag, grease band, namhar band, grease + black oil and black oil cloth bands were applied, respectively. The interactional response between different bands and dates of observation reveal that the effect of Haider’s band at all the dates of observation showed non-significant difference and resulted in the lowest population of the pest crossed the band. Cotton wool band found less effective resulted in maximum population of mango mealybug crossed the band at all the dates of observation as compared to other bands. The population increased gradually at all the observations in all the treatments except Haider’s band. Table 6. MEAN COMPARISON OF THE DATA REGARDING PERCENT POPULATION CROSS THE TESTING BAND DURING 2006 AND 2007.
Dates x Treatments (**) Treatments LSD=4.0015 Means (**) Treatments LSD Jan. 7 Jan. 14 Jan. 21 Jan. 28 Feb. 4 Feb. 13 Feb. 19 =1.1796 A B C D E F G H Namhar Band 0.00 z 2.31 yz 20.48 s 42.03 49.09 ij 51.81 hi 50.92 i 30.95 d lm Black Oil 0.00 z 3.69 yz 9.14 x 12.03 15.19 23.31 rs 29.71 q 13.29 f Cloth vwx tuv Gunny Bag 0.72 yz 16.32 36.03 47.57 j 58.02 ef 66.56 c 62.61 d 41.12 b tu op Grease Band 0.00 z 3.19 yz 32.88 p 41.58 46.23 jk 54.46 gh 55.21 fg 33.37 c lm Grease+Black 0.00 z 2.59 yz 24.17 r 33.41 p 39.98 41.86 lm 43.64 kl 26.52 e Oil mn Funnel Type 0.00 z 1.04 yz 3.02 yz 9.16 x 13.01 13.21 11.71 7.31 h Trap uvw tuvw vwx Cotton Wool 1.02 yz 13.62 37.51 42.45 58.78 e 77.82 a 70.47 b 43.09 a Band tuvw no lm Polyethylene 0.00 z 1.53 yz 4.02 y 10.54 14.34 15.84 tu 15.84 tu 8.87 g Sheet Band wx tuv Plastic Sheet 0.00 z 1.74 yz 3.96 y 10.33 16.55 tu 16.89 t 15.93 tu 9.34 g Band wx Haider’Band 0.00 z 0.00 z 0.55 yz 0.86 yz 0.99 yz 0.93 yz 0.91 yz 0.61 i
LSD =0.9869 0.17 f 4.60 e 17.18 d 24.99 c 31.22 b 36.27 a 35.69 a Df=54 F-value= 82.5 Df=9 F- value=1311.2 Bands (n=10) Means sharing similar letters in columns A to G for interaction and in column H for treatment means did not differ significantly by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
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7.3.3 CHEMICAL CONTROL OF MANGO MEALYBUG Eleven formulated insecticides viz., profenophos (Curacron 500 EC), bifenthrin (Talstar 10 EC), triazophos (Hostathion 40EC), chlorpyrifos (Lorsban 40 EC), lambdacyhalothrin (Karate 2.5EC), imidacloprid (Confidor 200SL), buprofezin (Starter 20SP), deltamethrin (Decis 2.5EC), cypermethrin (Ripcord 10EC), acetamiprid (Mospilan 20SP), and methidathion (Supracide 40EC) at the rate of 9 µl, 30 µl , 30 µl, 15 µl, 15 µl, 30 µl, 150 µg, 15 µl, 30 µl, 30 µl and 45 µl, respectively, were tested in 30 ml of water for the control of mango mealybug under laboratory as well as under field conditions. The results are as follows. 7.3.3.1 In Vivo Mortality of Mango Mealybug One Day After Treatment The results regarding chemical control of first instars of mango mealybug in different treatments at one day post-treatment interval under laboratory conditions show highly significant (P ≤ 0.01) differences among treatments. The means were compared by DMR Test at P=0.05 (Table 7, Column A). The results reveal that Acetamiprid at the rate of 100 g / 100 liter water showed maximum mortality of first instar nymph of mango mealybug i.e. 33 percent and differed significantly from those of observed in all other treatments. Imidacloprid at the rate of 100 g/100 liter water was the next effective insecticide resulted in 28 percent mortality of the pest and also differed significantly from all other treatments. The effectiveness of other insecticides in descending order were bifenthrin > triazophos = deltamethrin > lambdacyhalothrin > chlorpyrifos= profenophos > buprofezin > cypermethrin > methidathion with 25, 20, 20, 18, 15, 15, 13, 10 and 5 percent mortality of first instars nymph after one day post treatment interval, respectively. 7.3.3.2 Mortality of Mango Mealybug Two Days After Treatment The results pertaining to mortality of first instar nymphs of mango mealybug at two days after treatments (Table 7 Column B). The results reveal highly significant (P ≤ 0.01) differences between treatments. Imidacloprid caused the highest mortality (65 percent) and differed significantly from those of obtained in all other treatments. Detamethrin was the next effective insecticide with 53 percent mortality of the pest and also differed significantly from all other treatments followed by acetamiprid (48 percent), cypermethrin (45 percent), lambdacyhalothrin (45 percent), buprofezin (40 percent),
139 Chapter 7 Sustainable Management of Mango Mealybug bifenthrin (35 percent), chlorpyrifos (33 percent), triazophos (30 percent), profenophos (23 percent) and methidathion (18 percent). 7.3.3.3 Mortality of Mango Mealybug Three Days After Treatment The data regarding morality of first instar nymph of mango mealybug three days after spray in different treatments (Table 7, Column C). The results showed significant (P ≤ 0.01) difference among treatments. The means were compared by DMR Test at P=0.05. Confidor at the rate of 100 g formulation/100 liter water resulted in maximum mortality of the pest i.e. 78 percent and differed significantly from those of observed in all other treatments. Acetamiprid, deltamethrin and buprofezin were the next effective insecticides each showed 73 percent mortality of first instar nymph at two days after treatment followed by profenophos, bifenthrin, chlorpyrifos, methidathion, cypermethrin, lambdacyhalothrin and triazophos with in 70, 68, 68, 65, 58, 55 and 53 percent mortality of first instar nymph of mango mealybug, respectively. 7.3.3.4 Mortality of Mango Mealybug 4 Days After Treatments Significant differences were found to exist between treatments regarding morality of first instars nymph of mango mealybug four days after treatment (Table 7, Column D). The use of Lambdacyhalothrin resulted in 100 percent mortality of the pest and differed significantly from those of observed in all other treatments. The application of acetamiprid, profenophos, bifenthrin, chlorpyrifos, imidacloprid, deltamethrin, buprofezin, cypermethrin and triazophos resulted in 93, 90, 88, 85, 83, 83, 80, 78 and 70 percent morality of first instars four days after treatment, respectively. All these treatments differed significantly from one another except imidacloprid and deltamethrin which showed similar response statistically with each other. The lowest mortality (66 percent) in the methidathion was applied and this treatment also differed significantly from all other treatments.
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Table 7. MEAN COMPARISON OF FIRST INSTAR MANGO MEALYBUG PERCENT MORTALITY UNDER LABORATORY CONDITION.
Treatments Percent mortality of first instar after Dose/ Dose/30 Total Two Three Four Five 100 ml insects One day Six day day day day day Common Name Trade name lit water water exposed A** B** C** D** E** F** 30ml 9 µl 40 15 f 22.50 i 70 c 90 c 100 a 100 a Profenophos 500EC Curacron 100ml 30 µl 40 25 c 35.00 f 67.50 d 87.50 d 100 a 100 a Bifenthrin 10EC Talstar 100ml 30 µl 40 20 d 30 h 52.50 h 70 i 87.50 e 100 a Triazophos 20EC Hostathion 50ml 15 µl 40 15 f 32.50 g 67.50 d 85 e 100 a 100 a Chlopyriphos 40EC Lorsban 50ml 15 µl 40 17.50 e 45 d 55.00 g 100a 100 a 100 a Lambdacyhalothrin 2.5EC Karate 100g 30 µl 40 27.50 b 65 a 77.50 a 82.50f 97.50 b 100 a Imidacloprid 200SL Confidor 500g 150 µg 40 12.75 g 40 e 72.50 b 79.50 g 90 d 100 a Buprofezin 20SP Starter 50ml 15µl 40 20.00 d 52.50 b 72.50 b 82.50 f 97.50 b 100 a Deltamethrin 2.5EC Decis 100ml 30 µl 40 10 h 45.00 d 57.63 f 77.50 h 87.50 e 97.50 b Cypermethrin 10EC Ripcord 100g 30 µl 40 32.50 a 47.50 c 72.50 b 92.50 b 100 a 100 a Acetamiprid 20 SP Mospilan 150ml 45 µl 40 5 i 17.50 j 65 e 65.50 j 92.50 c 100 a Control Control - 40 0 j 0 k 0 i 0 k 0.00f 0.00 c LSD @5% 1.191236 1.0241 1.1108s 1.4764 0.51706 0.1434079 F-value 497.0 2330.3 2831.5 2507.5 3152.1 239059.1 n=12 df= 11 Means sharing similar letters in columns are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
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7.3.3.5 Mortality of Mango Mealybug 5 Days After Treatment The treatment effect on the mortality of first instar nymphs of mango mealybug at five days after application was significant (Table 7, Column E). Profenophos, bifenthrin, chlorpyrifos, lambdacyhalothrin and acetamiprid showed 100 percent mortality of the pest and these treatments differed significantly from all other treatments. Statistically similar response was observed between triazophos and cypermethrin, imidacloprid and deltamethrin with 88 and 98 percent mortality for each pair, respectively. The application of buprofezin and methidathion showed 90 and 93 percent mortality of the nymphs of mango mealybug, respectively and differed significantly from each other. 7.3.3.6 Mortality of Mango Mealybug 6 Days After Treatment All the insecticides showed 100 percent mortality of the pest except cypermethrin with 98 percent mortality and showed significant difference with all other insecticides. (Table 7, Column F). Conclusion All the insecticides showed 100 percent mortality of the pest 6 days after treatment except cypermethrin which showed 98 percent mortality. 7.3.3.7 Mortality of First Instar Mango Mealybug under Field Conditions Same insecticides tested under laboratory conditions were evaluated for their efficacy against first nymphal instars of mango mealybug under field conditions for two years viz., 2006 and 2007. 7.3.3.7.1 Mortality of First Instar Mango Mealybug 24 Hours After Spray
The data regarding percent mortality of first instar nymphs of mango mealybug 24 hours after spray are given in (Table 8, Column A). Highly significant differences were found between treatments whereas the interaction between year and treatment was nonsignificant. The maximum mortality of the pest was observed in those treatments where acetamiprid and deltamethrin were applied with 80 and 78 percent mortality of the pest, respectively and did not show significant difference with each other followed by 75, 75 and 74 percent mortality in those treatments where methidathion, lambdacyhalothrin and profenophos were sprayed, respectively and did not show significant difference with one another. The minimum morality of the pest i.e. 44 percent observed in those trees
142 Chapter 7 Sustainable Management of Mango Mealybug where cypermethrin was sprayed and differed significantly from all other treatments. The effect of other insecticides in descending order is: Imidacloprid > chlorpyrifos > bifenthrin > buprofezin > and triazophos with 70, 67, 66, 64 and 53 percent mortality of the pest, respectively 24 hours after spray. 7.3.3.7.2 Mortality of First Instar Mango Mealybug 72 Hours After Spray
Variations were found to be significant among treatments as well as between interaction of years and treatments (Table 8, Column B). The highest mortality of the pest was recorded to be 85 percent in those trees where acetamiprid was sprayed and there was no significant difference with those of where lambdacyhalothin and profenophos (85 and 83 percent) mortality of first instar nymphs of mango mealybug, 72 hours after spray. The lowest mortality of the pest was observed to be 60 and 61 percent in those trees where cypermethrin and triazophos were sprayed, respectively and did not show significant difference with each other. The application of deltamethrin, methidathion, chlorpyrifos, imidacloprid, bifenthrin and buprofezin resulted in 81, 78, 76, 75, 73 and 66 percent mortality of first instar nymphs of the pest, respectively. 7.3.3.7.3 Mortality of First Instar Mango Mealybug 168 Hours After Spray
Significant differences were found between treatments means, interaction between years and treatments and between years regarding mortality of first instar nymphs of mango mealybug 168 hours after spray (Table 8, Column C). The results reveal that acetamiprid was found to be the most effective insecticide resulted in maximum mortality of the pest i.e. 91 percent and differed significantly from those of observed in all other treatments. Methidathion, lambdacyhalothrin and deltamethrin showed similar response statistically with 86, 86 and 85 percent mortality of first instars nymphs of mango mealybug, respectively and ranked second in their effectiveness after acetamiprid. The mortality of the pest observed in those treatments where deltamethrin was applied also showed no significant difference with those of observed in profenophos treatment. The mortality on the pest was recorded to be 78 and 78 percent in those treatments where chlorpyrifos and imidacloprid were sprayed, respectively. Cypermethrin was found to be the least effective resulted in 65 percent mortality of the pest and differed significantly from those of observed in all other treatments. Nonsignificant variation was
143 Chapter 7 Sustainable Management of Mango Mealybug also found to exist between those treatments where bifenthrin and buprofezin were sprayed resulted in 74 and 72 percent mortality of the pest. 7.3.3.8 Mortality of Second and Third Instars Mango Mealybug Similar insecticides were evaluated for their effectiveness against second and third nymphal instars of mango mealybug under field conditions during 2006 and 2007. The observation was recorded at various post treatment intervals. The results are as follows. 7.3.3.8.1 Mortality of Second and Third Instars Mango Mealybug 24 Hours After Spray. The data regarding percent mortality of second and third nymphal instars of mango mealybug observed at 24 hours after spray during 2006 and 2007 are given in Table 8, Column D. Highly significant differences were found among treatments. The means were compared by DMR Test at P=0.05. The maximum mortality of second and third nymphal instar was recorded to be 71 percent in those treatments where deltamethrin was sprayed and did not show significant difference with those of observed in profenophos treatment showing 70 percent mortality of second and third nymphal instars of mango mealybug. Acetamiprid was found to be the next effective treatment with 65 percent mortality of the pest and also did not show significant variation with those of where lambdacyhalothrin and chlorpyrifos were sprayed showing 63 and 62 percent mortality of the pest. The later mentioned treatments also showed nonsignificant difference with those of where imidacloprid and methidathion were sprayed showing 58 and 60 percent mortality of the pest, respectively. No significant difference was also found to exist between bifenthrin and triazophos application with 51 and 47 percent mortality of the pest, respectively. Buprofezin was the least effective insecticide with 27 percent mortality of second and third nymphal instars of mango mealybug and differed significantly from the mortality observed in all other treatments. Similarly the application of cypermethrin also showed discouraging results i.e. 38 percent mortality of the pest and also differed with those of found in all other treatments.
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Table 8. MEAN COMPARISON OF CHEMICAL CONTROL OF MANGO MEALYBUG FIRST INSTAR, SECOND & THIRD INSTAR AND ADULT FEMALE UNDER FIELD CONDITION DURING 2006-2007 (AVERAGE OF BOTH YEARS).
Insecticide 1st instar 2nd and 3 rd instar Adult female Dose / Percent mortality after Percent mortality after spray Percent mortality after spray 100 lit spray Common Name Trade name water 24 h 72 h 168 h 24 h 72 h 168 h 24 h 72 h 168 h A** B** C** D** E** F** G** H** I** Profenophos 500EC Curacron 30ml 74.42 b 83.35 a 83.68 c 70.02 a 72.52 c 78.84 b 50.11 c 62.24 c 64.44 c Bifenthrin 10EC Talstar 100ml 65.80 de 73.48 e 74.11 e 51.12 e 55.50 h 58.71 g 26.15 i 29.83 h 33.37 h Triazophos 20EC Hostathion 100ml 52.94 f 61.27 g 68.00 f 47.34 e 57.66 g 62.03 f 30.12 h 33.39 g 35.55 g Chlorpyrifos 40EC Lorsban 50ml 66.70 d 76.25 cd 77.68 d 61.94 bcd 66.39 e 70.11 d 35.19 f 46.77 e 52.99 e Lambdacyhalothrin 2.5EC Karate 50ml 74.85 b 84.98 a 86.32 b 63.43 bc 64.87 f 74.88 c 31.89 g 42.35f 52.54 e Imidacloprid 200SL Confidor 100g 70.47 c 75.22 de 77.50 d 57.89 d 64.02 f 67.76 e 40.28 e 45.26 e 48.61 f Buprofezin 20SP Starter 500g 63.57 e 66.19 f 72.26 e 26.95 g 28.59 j 33.86 i 6.36 k 11.50 j 16.36 i Deltamethrin 2.5EC Decis 50ml 77.93 a 80.91 b 85.20 bc 70.72 a 74.55 b 77.22 b 45.44 d 54.02 d 61.58 d Cypermethrin 10EC Ripcord 100ml 4.80 g 60.05 g 64.92 g 37.61 f 42.65 i 45.83 h 21.87 j 25.12 i 32.96 h Acetamiprid 20 SP Mospilan 100g 79.72 a 85.17 a 90.57 a 65.25 b 77.99 a 81.42 a 58.13 b 69.39 b 70.57 b Methidathion 40EC Supracide 150ml 75.48 b 77.76 c 86.18 b 60.23 cd 69.86 d 74.02 c 59.89 a 71.64 a 72.71 a Control Control 0.00 h 0.00 h 0.00 h 0.00 h 0.00 k 0.00 j 0.00 l 0.00 k 0.00 j LSD @ 5% 2.3723 2.066 2.3723 4.507 1.516 1.969 1.660 1.993 1.828 F-value 697.9 1008.0 1085.3 168.3 1763.5 1151.7 1004.3 982.5 1171.7 n=12 df= 11 Means sharing similar letters are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
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7.3.3.8.2 Mortality of Second and Third Instars Mango Mealybug 72 hours After Spray. The data regarding percent mortality of second and third nymphal instars of mango mealybug at 72 hours after spray during 2006 and 2007 in different treatments (Table 8, Column E). The results reveal highly significant differences between treatments and interactions between years and treatments. It is evident from the results that methidathion was found to be the most effective treatment causing the greatest mortality at 78 percent 72 hours after spray of all insecticides tested. Deltamethrin was found to be the most effective treatment resulted in 74 percent mortality of the pest and also showed significantly different from all other treatments. The effectiveness of all other treatments in descending order was profenophos > methidathion > chlorpyrifos > lambdacyhalothrin = imidacloprid > triazophos > bifenthrin > cypermethrin > and buprofezin with 73, 70, 66, 65, 64, 58, 56, 43, and 29 percent mortality of the pest, respectively. 7.3.3.8.3 Mortality of Second and Thir Instars Mango Mealybug 168 Hours After Spray. The data relating to mortality percentage of second and third nymphal instars of mango mealybug in different treatments at 168 hours after spray are given in (Table 8, Column F). The results reveal highly significant differences between treatments and between years and a significant interaction between year and treatment. Acetamiprid was most effective with the highest mortality at 81 percent and differed significantly from those of observed in all other treatments followed by 79, 77, 75, 74, 70, 68, 62 and 59 percent mortality of the pest in those trees where profenophos, deltamethrin, lambdacyhalothrin, methidathion, chlorpyrifos, imidacloprid, triazophos and bifenthrin, respectively were applied. Buprofezin was found to be the least effective resulted in minimum morality of the pest i.e. 34 percent and differed significantly from those of recorded in all other treatments. 7.3.3.9 Mortality of Adult Female of Mango Mealybug at Various Post Treatments Intervals. Same insecticides were evaluated for their efficacy against adult female of mango mealybug during 2006 and 2007. The observations were recorded 24 hours, 72 hours and 168 hours after spray. The results are given as follows.
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7.3.3.9.1 Mortality of Adult Female of Mango Mealybug 24 Hours After Spray. The data regarding percent mortality of adult females of mango mealybug at 24 hours of post treatment intervals in different treatments during 2006 and 2007 are presented in (Table 8, Column G). The result showed significant differences among treatments as well as interactions of years and treatments. The results reveal that methidathion was found to be the most effective causing 60 percent mortality followed by 58, 50, 45, 40, 35, 32, 30, 26 and 22 percent mortality of the pest in those treatments where acetamiprid, profenophos, deltamethrin, imidacloprid, chlorpyrifos, lambdacyhalothrin, triazophos, bifenthrin and cypermethrin, respectively were sprayed. Buprofezin showed the least toxic effect on the adult female of mango mealybug resulted in minimum mortality i.e. 6 percent. All the insecticides mentioned above showed significant differences with one another. 7.3.3.9.2 Mortality of Adult Female of Mango Mealybug 72 Hours After Spray. The data pertaining to the mortality percentage of adult females of mango mealybug at 72 hours of post treatment interval during 2006 and 2007 are shown in (Table 8, Column H). The results reveal highly significant differences among treatments. Methidathion was found to be the most effective and resulted in maximum mortality of the pest i.e. 72 percent followed by 69, 62 and 54 percent mortality of the pest in those treatments where acetamiprid, profenophos and deltamethrin, respectively were sprayed. Chlorpyrifos and imidacloprid showed 47 and 45 percent mortality of the pest, respectively and did not show significant variation with each other. Buprofezin was found to be the least effective insecticide for the control of adult female of mango mealybug resulted in 12 percent mortality and also differed significantly from those of observed in all other treatments. The effectiveness of other insecticides in descending order are lambdacyhalothrin, triazophos, bifenthrin and cypermethrin with 42, 33, 30 and 25 percent mortality of the pest, respectively. 7.3.3.9.3 Mortality of Adult Female of Mango Mealybug 168 Hours After Spray. The data regarding mortality of adult females of mango mealybug in different treatments 168 hours after spray during 2006-2007 are given in (Table 8, Column I). The result of the same reveals highly significant difference among treatments. The means were compared by DMR Test at P=0.05. Methidathion was found to be the most effective
147 Chapter 7 Sustainable Management of Mango Mealybug resulted in maximum mortality of the pest i.e. 73 percent and showed significant difference with the mortality observed in all other treatments. Acetamiprid was found to be the second most effective insecticide with 71 percent mortality of the pest and also differed significantly from all other treatments. Buprofezin did not show good control of the pest and showed minimum mortality i.e. 16 percent and also showed significant difference with those of observed in all other treatments. The mortality percentage was ranked as 64, 62, 53, 53, 49, 36, 33 and 33 in those treatments where profenophos, deltamethrin, chlorpyrifos, lambdacyhalothin, imidacloprid, triazophos, bifenthrin and cypermethrin, respectively were sprayed. 7.3.3.10 SUSTAINABLE MANAGEMENT APPROACH FOR THE CONTROL OF MANGO MEALYBUG From the selectivity studies, the control methods which found the most effective were integrated with the objective to develop a sustainable strategy to control the mango mealybug. Mounding the trunk with the materials present under the plants like dried leaves, branches, weeds, clods of mud, debris after spreading plastic sheet (cultural control), Haider’s band (mechanical control) and acetamiprid @100g/100 liter water (chemical control) were applied individually and as well as in their possible interactions viz., mechanical + chemical, cultural + mechanical, cultural + chemical and cultural+ mechanical + chemical for the control of mango mealybug. The data regarding the population of first instar nymph were recorded from the tree trunk 45 cm above the ground level before the treatment during 2006-2007. After recording the data the above mentioned practices were applied to the selected trees. The post treatment data were recorded during the year 2008. The percent reduction over control of the pest was calculated. The data on percent reduction of mango mealybug in different treatments are given in (Table 9). The results showed significant difference (P < 0.01) among different treatments. The maximum reduction (98 percent) of mango mealybug was observed on the trees where cultural + mechanical + chemical methods were used followed by cultural + chemical, cultural + mechanical and mechanical + chemical with 88, 81 and 78 percent reduction of mango mealybug, respectively.
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Table 9. MEANS COMPARISON OF THE DATA REGARDING PERCENT REDUCTION OF MANGO MEALYBUG IN DIFFERENT IPM METHODS DURING 2006 TO 2008.
Before treatment Percent population population during Treatments /Practices reduction over control 2007(05.01.07 to 16.02.07) after treatment (**) (ns) T1- Cultural 204.29 70.58 e T2- Mechanical 178.62 45.23 g T3- Chemical 168.90 48.68 f T4- Cultural X Mechanical 211.14 81.32 c T-5 Cultural X Chemical 208.33 87.70 b T6- Mechanical X 188.86 78.03 d Chemical T7- Cultural X Mechanical 211.90 98.46 a X Chemical T8-Control 205.24 0.00 h LSD @ 5% 68.8554 1.05286 D.F=7 F-value=7975.4 Means sharing similar letters for means did not differ significantly by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
A significant low reduction (45 percent) of mango mealybug was observed in mechanical treatment compared with all of the other treatments used. Chemical methods of control and cultural control resulted in 48 and 71 percent reduction in mango mealybug, respectively and showed significant difference with each other. From the data it could be suggested that the combination of cultural, mechanical and chemical methods gave better control for MMB. Cost Benefit Ratios (CBR) was calculated (Table 10 & 11) to find the economics and feasibility of each control practice. The results reveal that a combination of mechanical + chemical and cultural practices showed maximum benefit to the farmers with the CBR 1:9 followed by the application of Acetamiprid at the rate of 1 gm per liter water only (1:6), application of Haider’s band (1:5), mechanical + chemical practices (1:3), cultural practice only (1:1), cultural + chemical (1:1) and cultural + mechanical practice (1:1). To avoid the use of insecticide, Haider’s band was proved to be effective, economical and easy to apply resulted in good benefit to the farmers.
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Table 10. COST BENEFIT RATIO IN DIFFERENT TREATMENTS REGARDING CONTROL OF MANGO MEALYBUG.
Treatment No. Name of Treatment CBR T1 Mounding and spreading the soil (cultural) 1:14 T2 Application of Haider’s band (mechanical) 1:48 T3 Application of Acetamiprid at the rate of 1gm/liter water 1:60 T4 Cultural + chemical 1:11 T5 Mechanical + cultural 1:10 T6 Mechanical + chemical 1:24 T7 Mechanical + cultural + chemical 1:92
Table 11. COST BENEFIT RATIO Practices Material required Approx.cost per tree • Cultural i)Plastic sheet Rs: 9 ii)Labor for Mounding the Rs:15 tree iii) Labor for Spreading the Rs:10 mounds Total cost Rs: 34 • Mechanical i)Plastic sheet Rs: 2.60 ii)Grease Rs: 4.00 iii)Nails Rs: 0.40 iv)Labor Rs: 3.00 Total cost Rs:10 • Chemical i)Insecticides required Rs: 4.00 below band on trunk ii)Labor for spray Rs: 4.00 Total cost Rs: 8 Grand Total Cost Cultural + Mechanical + Chemical Rs:52 per tree Average yield expected per tree 6 mounds loss 80 percent Increase due to control of mango mealy bug 4.8 mounds Rate / mound is average Rs: 1000 Cost Benefit Ratio 1000 x 4.8 = 4320 / 52 1:92
7.3.3.11 MANAGEMENT OF MANGO MEALYBUG MALES . i. Pupae of male mango mealybug were exposed to sunlight by hoeing five cm deep under tree trunk in semi wet soil and in dry soil, near water channel (semi wet soil) under leaves in semi wet soil and dry soil and on the tree trunk bark to record the
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emergence of male mango mealybug. The experiment was conducted in a mango garden of 10 acres near Multan. The data regarding number of exposed pupae of male mango mealybug were recorded. The data reveals highly significant difference among treatments. The means were compared by DMR Test at P=0.05 (Table 12). The maximum number of pupae 56 per 900 cm 2 was observed near katcha water channel in semi wet soil and differed significantly from all treatments. The number of pupae 45 per 900 cm 2 was observed under tree trunk and also differed significantly from all other treatments. The number of pupae 5, 4 and 1 per 900 cm 2 observed under tree trunk (dry soil), under leaves (dry soil) and on the tree trunk bark, respectively did not show significant difference with each other. The number of pupae 12 per 900 cm 2 under leaves (semi-wet soil) differed significantly from those of observed in all other treatments. From these results it was observed that semi-wet soil near katcha water channel was found to be the most favourite pupation site for male mango mealybug followed by semi-wet soil under tree trunk. The emergence of winged males was recorded to be zero in all the experimental sites. Table 12. MEAN COMPARISON OF DATA REGARDING PUPAE OF MANGO MEALYBUG PER 900 CM 2 IN ORCHARD IN DIFFERENT PLACES DURING 2007.
TREATMENTS TREATMENT MEANS (**) Under tree trunk (Semi-wet soil) 46.75 b Under tree trunk (Dry soil) 5.37 d Near kacha water channel (Semi-wet soil) 55.63 a Under leaves (Semi-wet soil) 12.25 c Under leaves (Dry soil) 3.75 d On tree bark 0.63 d LSD@5% 5.451 D.F=5 F-value=158.7 Means sharing similar letters are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
151 Chapter 7 Sustainable Management of Mango Mealybug ii. Light traps of different colours viz., yellow, red, mercury, blue and green were installed in the mango orchards with the objective to monitor the winged males of mango mealybug during their peak activity in the month of Apr. for disrupting their mating with virgin female. The data showed highly significant differences among different colours of light trap and date of observation. The means were compared by DMR Test at P=0.05 (Table 13). It is evident from the results that mercury light attracted the maximum winged males i.e. 5.71 per day and differed significantly from those of observed in all other lights. Yellow, red, blue and green colored lights showed nonsignificant differences with one another resulted in a range of male catches 0.13 to 0.21 per trap per day. As regard to the variation among dates of observation, it was observed that Apr. 16, 2007 was the most favorite date resulted in maximum moth catches i.e. 1.93 per day per trap and did not show significant variation with those of Apr. 14, 15, 17 and 18 with 1.53, 1.67, 1.67 and 1.47 moths per day per trap, respectively. The moth catches decreased thereafter on Apr. 19 with 0.60 moths per trap per day. The moth catches of 0.13 per day per trap were observed on Apr. 20, 2007 which was the minimum. From these results it was observed that mercury light was the most effective for moth monitoring and Apr. 16, 2007 was the most favourable date of moth catches resulted in maximum individuals i.e. 1.94 per day per trap. Furthermore, mercury light showed maximum catches throughout the monitoring period as compared to all other lights. The maximum moths of males mango mealybug was attracted on Apr. 17 i.e. 8.00 per day per trap, whereas minimum on Apr. 20, 2007 i.e. 0.67 per trap per day. The effect of different lights on the moth population at various dates of observation reveals that yellow, red, blue, and green light did not show significant difference among dates of observation resulted in very low moth population catches which ranged from 0 to 0.7 per trap per night. Mercury light resulted in significant difference among dates of observation. The maximum moth catches was recorded to be 8.0 per trap per night on 17- 04-07 and did not show significant difference with those of recorded on 15-04-07 and 16-04-07 each resulted in 7.7 moths per trap per night. This population decreased thereafter on subsequent dates of observations. From these result it is concluded that mercury light is an effective for monitoring the pest as compared to all other lights under study.
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Table 13. MEAN COMPARISON OF POPULATION OF ADULT MALE MANGO MEALYBUG ATTRACTED TO DIFFERENT LIGHTS DURING 2007 .
Dates X Lights (**) LSD =1.04 Dates Yellow Red Mercury Blue Green Average (**) LSD=0.46 13-04-07 0.00 e 0.00 e 6.33 c 0.00 e 0.00 e 1.27 b 14-04-07 0.67 e 0.33 e 6.67 bc 0.00 e 0.00 e 1.53 ab 15-04-07 0.33 e 0.00 e 7.67 ab 0.33 e 0.00 e 1.67 ab 16-04-07 0.67 e 0.33 e 7.67 ab 0.67 e 0.33 e 1.93 a 17-04-07 0.00 e 0.00 e 8.00 a 0.00 e 0.33 e 1.67 ab 18-04-07 0.00 e 0.33 e 6.00 c 0.33 e 0.67 e 1.47 ab 19-04-07 0.00 e 0.00 e 2.67 d 0.33 e 0.00 e 0.60 c 20-04-07 0.00 e 0.00 e 0.67 e 0.00 e 0.00 e 0.13 d Average 0.21 b 0.13 b 5.71 a 0.21 b 0.17 e D.F 28 7 F-value 9.9 13.7 Means sharing similar letters are not significantly different by DMR Test at P = 0.05 LSD = Least Significant Difference Value. * = Significant at P < 0.05. ** = Significant at P < 0.01.
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7.4 DISCUSSION
Mango mealybug is a serious threat for mango orchards. These studies were conducted for the control of the pest by applying different control methods viz., cultural, mechanical and chemical. The most effective treatments were then integrated for sustainable management approach to control the pest. Results are discussed under the following sub-sections. 7.4.1 CONTROL OF MANGO MEALYBUG THROUGH CULTURAL PRACTICES Various cultural practices viz., hoeing/ploughing (T1), mounding/earthing the trees with fine mud (T2), mounding/ earthing the trees with debris, dried leaves, small branches, clods of mud (T3), mounding/earthing the trees on the plastic sheet with debris, dried leaves, small branches, clods of mud (T4) were applied for the control of mango mealybug in 2006 and 2007. The results revealed that mounding/earthing the trees on the plastic sheet with debris, dried leaves, small branches and clods of mud proved to be the most effective resulted in maximum reduction of nymphal population of mango mealybug. In contrast Sial (1999) reported complete control of the pest using hoeing or ploughing, use of burlap band, burning of adult female and removal of soil contaminated with eggs of mango mealybug gave complete control of the pest without pesticides. While Singh (1947), Haq and Akmal (1960), Sandhu et al., (1980) and Agricola et al., (1989) have shown digging the soil, burning of rubbish, scrapping of soil at the basis of fruit trees, root opening and pruning were the most effective methods. In the present study hoeing and ploughing resulted in 42 percent nymphal reduction, which was not an encouraging control. Similar results were also observed by Rahman and Latif (1944) who reported that destruction of eggs by digging them out with spades from the soil is not an encouraging practice. The present findings can partially be compared with those of Mohyuddin and Mahmood (1993) who achieved the control of mango mealybug by hoeing or ploughing the soil to a depth of 15 cm, 3 times between June and Dec. However, Xu et al., (1999) have used trenches filled with trash to trap egg-carrying females while moving downward from tree for egg laying. In a second experiment two
154 Chapter 7 Sustainable Management of Mango Mealybug treatments viz., removal of soil around the trunk in the month of Nov. and intercropping of oat and berseem as fodder on Sept. and Oct., respectively were tested for the control of mango mealybug. Two years studies revealed that intercropping resulted in significantly maximum reduction of nymphal population (77 percent) in those trees where Oat and berseem were intercropped whereas minimum nymphal reduction (64 percent) was found in those trees where soil was ploughed and removed. 7.4.2 CONTROL OF MANGO MEALYBUG THROUGH MECHANICAL METHODS Various mechanical methods in the form of bands viz., namhar band, black oil cloth band, gunny bag, grease band, grease + black oil, funnel type tape, cotton band, polyethylene sheet, plastic sheet and Haider’s band were applied for the control of mango mealybug for two years (2005-2007). The results of both years study revealed that Haider’s band was found to be the most effective and lowest cost method resulting in the least percent of nymphs i.e. 1 percent crossing the band. The number of nymphs crossing the other banding methods was from 7 to 43 percent. In contrast, Sial (1999), Abrar-ul- Haq et al., (2002), Satish (2003) used grease and plastic sheets to prevent upward movement of mango mealybug. From polyethylene sheet band and black oil cloth only 9 percent and 13 percent nymphs crossed during upward movement. Similarly Bindra and Sohi (1974) and Rahman and Latif (1944) also have shown effectiveness of the bands in preventing upward movement of mealybug. The namhar band however, was not very effective band as it resulted in 31 percent nymphal upward movement. The results are in line with those of Husain (1920) who found that the cotton bands are not effective in preventing the mealybug, Drosicha (Monophelebus ) sp. from reaching the blossoms of mango trees. 7.4.3 CONTROL OF MANGO MEALYBUG THROUGH INSECTICIDES Eleven formulated insecticides viz., profenophos (Curacron 500 EC), bifenthrin (Talstar 10EC), triazophos (Hostathion 20EC), chlorpyrifos (Lorsban 40EC), lambdacyhalothrin (Karate 2.5EC), imidacloprid (Confidor 200SL), buprofezin (Starter 20SP), deltamethrin (Decis 2.5EC), cypermethrin (Ripcord 10EC), acetamiprid (Mospilan 20SP), and methidathion (Supracide 40EC) at the rate of 30-ml, 100-ml, 100- ml, 50-ml, 50-ml, 100-g, 500-g, 50-ml, 100-ml, 100-g and 150-ml per 100 litre water, respectively were tested for the control of mango mealybug under laboratory as well as
155 Chapter 7 Sustainable Management of Mango Mealybug under field conditions. Acetamiprid was found to be the most effective insecticide in laboratory and in field conditions since most of the post treatment intervals resulted in significantly the highest mortality of different instars and adult females. Furthermore, all the insecticides resulted in 100 percent control of 1 st instars nymphs of mango mealybug under laboratory conditions six days after application but under field conditions acetamiprid is identified as the most effective insecticide for 1 st , 2nd and 3 rd instars nymphs of mango mealybug at 24, 72 and 168 hrs after treatment. Methidathion was the most effective for adult female at all the post treatment intervals under field conditions. Chlorpyrifos was not as effective. These findings are partially in conformity with those of Sarivastava and Tandon (1981) who reported that chlorpyrifos was toxic to mango mealybug compared with the insecticides other than those tested in the present study. The present findings can not be compared with those of Rojanavongse and Charernson (1984), Azim (1985), Dalaya et al., (1983), Rao and Barwal (1985), Khan (1985), Das and Singh (1986), Khurana and Verma (1988), Gaffar (1989), Singh et al., (1991), Sohi et al., (1992), Irulandi (2000) due to differences in their materials and methods. In the present study, buprofezin was the effective after 6 days resulting in 100 percent and lambdacyhalothin after 4 days with 100 percent mortality of nymphal instars of mango mealybug after spray under laboratory conditions. Similar results were observed by Srivastava (1997). Further it is pointed out that sole reliance on a single insecticide will result in the development of insecticide resistance in the insect populations. But if the farmers are going to make more than one application per year they need to rotate insecticides classes. 7.4.4 SUSTAINABLE MANAGEMENT APPROACH FOR THE CONTROL OF MANGO MEALYBUG From the above studies, the most effective control methods were mounding/earthing the trees on the plastic sheet with debris, dried leaves, small branches, clods of mud (cultural method), Haider’s band (mechanical method) and acetamiprid at the rate of 100-g per 100 litre water were applied individually as well as in their possible interactions for the control of mango mealybug on mango trees. The results revealed that a combination of cultural + mechanical + chemical methods resulted in maximum
156 Chapter 7 Sustainable Management of Mango Mealybug reduction (98.5 percent) of mango mealybug. The present findings can partially be compared with those of Tandon and Verghese (1995), Gul et al., (1997) and Bajwa and Gul (2000) who recommended a combination of cultural, mechanical and chemical control methods for the control of mango mealybug on mango trees but the methods they reported were different from those of tested in the present dissertation. The present findings can not be compared with those of Hartless (1914), Ali (1980), Lakra et al., (1980), Anwar (1991), Jia et al., (2001) and Ishaq et al., (2004) due differences in their materials and methods. It is noted that the greater effect of control methods in cultivars with greater susceptibility and can be adopted easily and could have immediate impact on production of mango. 7.4.5 MANAGEMENT OF MALES OF MANGO MEALYBUG Infestation to mango orchards caused by mango mealybug can be minimized by controlling an effective measure for management of male. For this purpose, emergence of males of mango mealybug was controlled with the help of light traps and cultural practices. It was observed that amongst yellow, red, mercury, blue and green lights, the males of mango mealybug were attracted to mercury light. It is therefore suggested that mercury light may be installed in the garden to capture the males of mango mealybug. The present findings cannot be compared with those of Rahman and Latif (1944) who used hurricane lanterns and two males per night were captured. Further it is noted that exposing male pupae to sunlight by hoeing 5 cm deep proved to be the most effective practice and resulted in maximum reduction.
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Chapter 8 SUMMARY
A comprehensive survey regarding views of the respondents relating to resistant and susceptible mango cultivars against mango mealybug, methods of spreading, places of hibernation, control practices, problems faced by the farmers and yield losses occurred due to the attack of mango mealybug in four districts of the Punjab viz., Bahawalpur, Rahim Yar Khan, Multan and Muzzaffar Garh after a preliminary survey during 2005 in Multan District. The results are summarized below. • MMB was reported to be the major insect pests of mango orchards followed by hoppers, fruit fly, scales, galls and midges • ‘Chaunsa cultivar’ was the most susceptible as viewed by the majority of the respondents i.e. 94 percent followed by 69, 63 and 63 percent respondents for ‘Fajri’, ‘Langra’ and ‘Black Chaunsa’, whereas 62 percent respondents had the view that ‘Dusehri’ was resistant cultivar for mealybugs. It is proved from the experiments that ‘Chaunsa’ is the most susceptible cultivar. The growers perception of the more resistant cultivars is agreement with the experimental evidence of the surveys conducted in study. The results show that Dusehri was more susceptible than other cultivars like Tukhmi or Anwar Ratul • Irrigation water was the major source of flare up of the pest as viewed by the majority of the respondents i.e. 94 percent followed by migrating pest from one place to another (52 percent), transportation of agricultural machinery (49 percent), through nursery plants (49 percent), by dissidence (33 percent), by host plants (41 percent), by weeds taken by the women from one place to another (28 percent), through air (18 percent) with farm yard manure (11 percent) and affected inflorescence by malformation (29 percent) • Majority of the respondents told that the pest hibernated under the trees followed by cracks in trees, mud walls around orchards, soil under tree canopy, roots of plants under fallen leaves and kacha (mud) water channels
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• The majority of the respondents (60 percent) adopted removal of weeds practice for the control of mango mealybug, resulting in 25 percent control as viewed by 85 respondents while hoeing, ploughing, irrigation and removal of weeds were also adapted by the respondents with variable results. Furthermore satisfaction level for the control of mango mealybug was unsatisfactory • Amongst 18 insecticides, diazinon and methidathion were the most common as 73 and 52 percent respondents gave positive response whereas, 29 and 48 percent respondents showed negative response, respectively. Furthermore, 86 respondents gave the view that diazinon controlled the mealybug up to 75 percent and 14 respondents reported 100 percent satisfaction. All the other insecticides did not give satisfactory results for the respondents • Grease bands were applied by the majority of the respondents for the control of mango mealybug. Forty three of the respondents reported up to 25 percent, whereas, 82 of the respondents reported 50 percent control of mango mealybug with this practice. The satisfaction level was again 50 percent or below • Lack of knowledge about the pest, lack of money, adulterated and shortage of pesticides, lack of unity amongst farmers and small land holdings were the main constraints for the control of mango mealybug • 100 percent yield losses was told by 23 percent respondents whereas 75 percent, 50 percent and 25 percent losses were reported by 35, 28 and 14 percent respondents, respectively • Burning of females scales, application of grease bands and insecticidal sprays did not give satisfactory results to the respondents for the control of fertilized females of mango mealybug migrating or dispersing down from the trees Population Dynamics The population dynamic studies were carried out on ‘Chaunsa’ cultivar as it was the most susceptible cultivar. The MMB population was observed on weeds around mango tree, on mango tree trunk, leaves, inflorescence and branches of the plant weekly from east, west, south and north sides. The data on the population of mango mealybug were also observed from the trunk of the trees and from the weeds around the trees.
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Predation, parasitization and fungal attacked specimens were also observed on the plant. The results are summarized as under: • South side showed maximum population of mango mealybug on leaves and inflorescence, whereas west side of the plant showed maximum population of mango mealybug on branches • Trunk of the plant showed maximum population of mango mealybug as compared to weeds. However, higher population was observed during 2005-2006 as compared to 2006-2007 • Parasitization and predation of the pest was higher during 2005-2006 as compared to 2006-2007 • Fungal attack was higher during 2006-2007 as compared to 2005-2006 Cultivar Resistance • Twelve cultivars of mango viz., ‘Chaunsa’, ‘Fajri’, ‘Langra’, ‘Black Chaunsa’, ‘Sufaid Chaunsa’, ‘Sindhri’, ‘Malda’, ‘Anwar Ratul’, ‘Dusehri’, ‘Ratul-12’, ‘Tukhmi’ and ‘Sensation’ were studied for their relative resistant/susceptibility against MMB in two years (2005- 2007) in district Multan. The population of mango mealybug was counted from leaves, inflorescence and branches at fortnight interval in their active period from East and South directions of the plant. The females of dominant similar size were collected from the trunk coming down the tree, and the specimens were weighed, and measured the length and width. The data on number of eggs laid per female, length and width of ovisac were also recorded on each cultivar. The results are summarized as under. • The ‘Chaunsa’ cultivar showed maximum population of mango mealybug in both the study years (105 and 70 during 2005-2006 and during 2006-2007, respectively) as well as on an average of both study years (87), whereas ‘Tukhmi’ cultivar was found comparatively resistant with minimum population of mango mealybug i.e. 18, 14 and 16 during 2005-2006, 2006-2007 and average of both years, respectively • On an average of both the study years, the following rankings positions towards susceptibility of mango cultivars were as follows
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• ‘Chaunsa’ > ‘Black Chaunsa’ > ‘Malda’ > ‘Fajri’ > ‘Ratul-12’ > ‘Langra’ > ‘Sensation’ > ‘Sindhri’ > ‘Dusehri’ > ‘Sufaid Chaunsa’ > ‘Anwar Ratul’ and > ‘Tukhmi’ • The maximum population range of mango mealybug was observed during 2 nd week of Feb. to 2 nd week of Mar. • The cultivar ‘Tukhmi’ appeared as comparatively resistant because of the minimum number of eggs laid per female, weight, length and width of female and length and width of ovisac • Based on biological parameters studies, the pest collected from ‘Chaunsa’ cultivar showed maximum weight, length and width of female, maximum length and width of ovisac and laid maximum number of eggs while all the above parameters were minimum on cultivar ‘Tukhmi’ Biology and Behaviour of the Pest • All the 1st instar nymphs molted in 56 days, 2 nd instar nymphs 26 days and 3rd instar nymphs 20 days. Nymphs were negatively geotropic and 1 st instar moved upward with average speed of 12 cm per minute, 2 nd instar 17 cm per minute and 3rd instar 37 cm per minute. The female laid eggs on an average of 282 in 13 days. First instar live without food for 12 days, 2 nd and 3 rd instar live for 13 days whereas adult female live 13 days without feeding. The average mating time for one female was 12 minutes Effect of environment on the population of Mango Mealybug • The maximum peak population of mango mealybug was observed to be 27 per 30-cm branch at maximum temperature of 25 ºC, minimum temperature of 10 ºC and RH 79 percent • All the weather factors under study did not show significant correlation with the population of mango mealybug • Relative humidity, on an average basis, played maximum role in population fluctuation of the pest i.e. explaining 25 percent of the variation in the insect fluctuation
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Period of Abundance The maximum population was observed from Feb. to Mar. But the population decreased from Apr. and onward as ambient temperature increased. Biochemical analysis of leaves and inflorescence Various chemical characters of the leaves and inflorescence such as nitrogen, potassium, crude fiber, fat, sodium, ash, carbohydrates, phosphorus, moisture and protein contents in different cultivars of mango viz., ‘Chaunsa’, ‘Fajri’, ‘Langra’, ‘Black Chaunsa’, ‘Sufaid Chaunsa’, ‘Sindhri’, ‘Malda’, ‘Dusehri’, ‘Anwar Ratul’, ‘Ratul-12’, ‘Tukhmi’ and ‘Sensation’ were processed for simple correlation and multiple linear regression analysis to determine the impact of these factors on the population fluctuation of the pest . The results are summarized below. • All the chemical plant factors on leaves and inflorescence differed significantly among various cultivars of mango • Maximum carbohydrate contents was observed in the cultivar ‘Chaunsa’ (susceptible to the pest), whereas minimum carbohydrates contents were observed in the cultivar ‘Tukhmi’ resistant to the pest. All the other factors did not show any specific sequence with the population of the pest in all the cultivars • Crude fiber, fat, sodium, ash and crude protein contents exerted significant and negative correlation with the population of mango mealybug on leaves, whereas potassium and carbohydrate resulted in a positive and significant correlation with the pest. Crude fiber and nitrogen contents were important which exerted negative and positive correlation with the pest population on inflorescence • Crude fiber and total ash played maximum role in the population fluctuation of mango mealybug and contributed 55.8 and 26.4 percent role, respectively. Furthermore the effect of all the factors when computed together resulted in 96.5 percent and 53.9 percent role in population fluctuation of the pest on leaves and inflorescence, respectively Losses caused by mango mealybug The study was conducted to observe the percent decrease in mango fruits on different cultivars of mango over treated trees during one season. Different control
162 Chapter 8 Summary methods were applied to trees with the objective to maintain the population of mealybug at zero level. The results are summarized as under. • The number of fruits were lower in the nontreated trees of all the cultivars was lower as compared to treated trees both at initial and final stage of the experiment • The maximum decrease in number of fruits was recorded 11 percent on cultivar ‘Anwar Ratul’, whereas ‘Langra’ cultivar showed minimum decrease in number of fruits at 3 percent over nontreated trees at initial stage of the experiment • At final stage of the experiment the maximum decrease in fruits was 81 percent on cultivar ‘Chaunsa’, whereas minimum decrease in fruits on cultivar ‘Tukhmi’ at 22 percent • On an overall basis, 44 percent decrease in fruits was recorded in nontreated trees at final stage of the experiment • A single mango mealybug can cause 3 percent loss in yield in inflorescence • Maximum population recorded on ‘Chaunsa’ cultivar was 18/inflorescence where as minimum population recorded on ‘Anwar Ratul’ was 10/inflorescence Sustainable management of Mango mealybug The selective studies were conducted with the objective to evaluate the most effective methods amongst various cultural (hoeing, mound with fine mud, mound with leaves, debris, grass and big clods, mound on the plastic sheet, intercropping and removal of soil), mechanical (Namhar band, black oil cloth, gunny bag, grease, grease + black oil, funnel type trap, cotton wool, polyethelene sheet, plastic sheet and plastic sheet with 1.5 inch grease ( Haider’s bands) and chemical insecticides viz., profenophos, bifenthrin, triazophos, chlorpyrifos, lambdacyhalothrin, imidacloprid, buprofezin, deltamethrin, cypermethrin, acetamiprid and methidathion during the year 2005 to 2007 in various orchards of mango at Multan. The results are summarized as under: • Amongst cultural practices mound on plastic sheet was found to be the most effective in reducing mango mealybug population • The application of plastic sheet with 3.7 cm wide layer of grease ( Haider’s band) proved to be the most effective resulted in the lowest individuals of the pest crossed the band on the tree trunk
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• Amongst various insecticides tested acetamiprid was found to be the most effective showing the highest mortality of the pest in almost all the nymphal instars followed by profenophos. Furthermore, methidathion resulted in maximum mortality of adult female of mango mealybug at all the post treatment intervals followed by acetamiprid • A combination of mounds on the plastic sheet, Haider’s band and application of acetamiprid were found to be the most effective treatment in reducing first instar nymphs. It is further stated that the Haider’s band was the most effective and cheaper which is a new addition in the mechanical control management mango mealybug • The males of mango mealybug were more attracted to mercury light as compared to other lights tested • Exposing male pupae to sunlight by hoeing 5-cm deep proved to be the effective practice resulted in maximum reduction
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8.1 RECOMMENDATIONS
FIG. 1 INTEGRATED MANAGEMENT SCHEDULE FOR MANGO MEALYBUG DROSICHA MANGIFERAE GREEN IN MANGO ORCHARDS
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8.2 CONDITION OF THE PEST AND RECOMMENDED PRACTICES
MMB Management schedule for the mango growers given below: Month Condition of the pest Recommendations December Hatching of the eggs started, a few Apply bands in first week nymphs started their movement in upward direction. Mostly feeds on weeds under the tree January Hatching continued and the nymphs Spray below the bands started ascend the trees in huge numbers February First instars nymphs settled on the If no bands applied spray the whole leaves and mostly on the tips of trees with profenophos @ 30 ml branches from which inflorescence /100liter water or any other suitable comes out insecticides March Nymphs changing the Instar and Spray the whole trees with enter the 2 nd shifting to the inflorescence, but & 3 rd instar shifting Acetamiprid @ males coming down the trees after 100 ml/100 litrer water or any other 20 th of this month suitable insecticides. Making of mounds for male collection and destruction. April Mating started and few females Cultural practices including mounding started decending the tree for egg around the trees trunk over plastic sheet laying before the 10 th of this month for the collection of egg carrying females May Almost all females completed their At this stage no effective management decent and males disappear practices of the pest can be adopted June Remaining females completed their Spread the mounds at the end of June downward movement and hibernate for the destruction of eggs. in mounds if present July Females laid egg in mounds or in Spread the mounds at any time in this their hibernated places month for the destruction of eggs August Eggs can be collected from the sides Spread the mounds at any time in this of kacha water channel, mud walls month for the destruction of eggs around the orchards and from the roots of host plants. September Eggs present in the orchards can be Intercropping of Oat and Berseem destroyed through intercropping of clover in orchards fodders October Eggs present in the orchards can be Intercropping of Oat and Berseem destroyed through intercropping of clover in orchards fodders November If eggs present in the roots of host Removal of eggs from the trunks and plant destroyed
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8.3 PRECAUTIONARY MEASURES
The following precautionary measures can be adopted by the mango growers to overcome this notorious pest
• Mango mealybug ( Drosicha mangiferae Green) has more than 70 host plants, so that cultural, mechanical and chemical controls should be applied with all the host plants • Application of grease is dangerous for the mango trunk so it should not be applied directly on the trunk of mango trees • Mango mealybug shifted from trees to trees through the branches so the the branches touching the trees should be cut off • Irrigation water is the main source of spreading the mango mealybug, the branches over the water channel should be trimmed off to avoid spreading to non infested orchards • Avoid purchasing nursery plants from the infested nurseries • Agricultural implements such as cultivator etc used in infested orchards should not be used in uninfested orchards • Avoid moving of weeds (taken by the women for animals as feed), trimmed malformed inflorescence and branches (for fuel purposes) of infested orchards to uninfested orchards • Recommended cultural, mechanical and chemical control methods should be adopted in time (which is the most important) to overcome this pest • Ask the fellow farmers to act upon the advices of agricultural experts
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APPENDICES
Appendix 1. DATA REGARDING FIRST STADIUM DURATION 1 Number of nymphs stop Busting of exiuvae Remained in on dated feeding on dated exiuvae th 15 of Dec ,2006 Collected eggs from the field kept in polyethelene bags for hatching 30,31 st Dec, 2006 416 nymphs of 1 st instar collected 1, 2 Jan, 2007 Kept in petri dish for 48 h 3 Nymphs released on 1 st and 2 nd plant, start go upward 4, Jan to 6 th Feb Feed leaves 2007 7th Feb. 4 11 th Feb 12 th Feb(24h) 8 0 - - 9 1 14 th 15 th 10 3 14 th 15 th 11 5 15 th 16 th 12 6 16 th 17 th 13 8 18 th 19 th 14 7 18 th 19 th 15 11 19 th 20 th 16 13 20 th 21 st 17 19 22 nd 23 rd 18 21 23 rd 24 th 19 33 24 th 25 th 20 41 25 th 26 th 21 83 25 th 26 th 22 105 26 th 27 th 23 23 28 th 1st March 24 12 28 th 1st 25 0 - - 26 1 3rd March 4th 27 0 3rd 4th 28 2 4th 5th 1, March, 2007 0 - - 2 1 7th 8th 3 0 - - 4 3 9th 10 th 5 0 - - 6 2 10 th 11 th 7 0 - - 8 1 12 th 13 th Total duration 4-5 days 1 day (45-68 days Av:56.5)
189 Appendices
Appendix 2. DATA REGARDING SECOND STADIUM DURATION
Date of collection Number of nymphs Busting of exiuvae Remained in 2nd stadium stop feeding on dated exiuvae on dated 25,26 th Feb,2007 188 nymphs of 3 rd instar collected 27 th Kept in petri dish for 24 h 28 th Nymphs were released on 3 rd plant, go upward 1st , March to 9 th Feed leaves and some on inflorescence March 10 2 13 th 14 th 11 0 - - 12 4 16 th 17 th 13 6 18 th 19 th 14 16 18 th 19 th 15 35 19 th 20 th 16 61 21 st 22 nd 17 35 21 st 22 nd 18 8 23 rd 24 th 19 13 24 th 25 th 20 0 - - 21 2 24 th 25 th 22 3 26 th 27 th 23 1 28 th 29 th 24 0 - - 25 2 29 th 30 th 26 1 30 th 30 th Total duration 4-5 days 1 day (18-34 days Av: 26)
190 Appendices
Appendix 3. DATA REGARDING THIRD STADIUM DURATION
Date of collection Number of nymphs Busting of exiuvae Remained in on 3rd stadium stop feeding on dated dated exiuvae 15,16 March,2007 96 nymphs of 3 rd instar collected 17 Kept in petri dish for 24 h 18 Released on 4 th plant and go upward 19- 24, March Feed on inflorescence 25 1 30 th March 30 th 26 7 30 h 31 st 27 13 31 st 1st April 28 25 2nd April 3rd 29 16 2nd 3rd 30 10 4th 5th 31 8 4th 5th 1st April 9 5th 6th 2nd 2 6th 7th 3rd 2 7th 8th 4th 3 8th 9th Total duration 4-6 days 1 day (15-24 days Av:19.5)
191 Appendices
Appendix 4. DATA REGARDING FEMALE DURATION
Date of collection female Females condition Number of Females moved down ward 22,23 rd March, 2007 41 female were collected 24, March Kept in petri dish for 24 h 25 Released on 5 th plant , go upward and mated 26 Feed on inflorescence 27 Covered with whitish powder during feeding on inflorescence 28, March to 5,April Same 6, April Same 1 7 Same 0 8 Same 0 9 Same 1 10 Same 1 11 Same 0 12 Same 0 13 Same 1 14 Same 0 15 Same 2 16 Same 1 17 Same 0 18 Same 1 19 Same 1 20 Same 4 21 Same 1 22 Same 7 23 Same 7 24 Same 4 25 Same 3 26 Same 2 27 Same 1 28 Same 0 29 Same 0 30 Same 0 1st , May, 2007 Same 1 2 Same 2 Total duration 16-42 days (Av:29 days)
192 Appendices
Appendix 5. DATA REGARDING MALES CAME DOWN THE TREE
DATED NUMBERS OF MALES DOWN THE TREE 01.04.07 NO 02.04.07 3 03.04.07 11 04.04.07 16 05.04.07 24 06.04.07 5 Total numbers of nymphs 59
Appendix 6. DATA REGARDING DISTANCE COVERED IN INCHES BY FIRST, SECOND AND THIRD INSTAR NYMPHS IN ONE MINUTE ON TREE
Nymphs Distance covered in inches /mintues 1st Instar 2nd Instar 3rd Instar 1 5 5 16 2 5 7 18 3 4.5 8 10 4 6 10 14 5 5 7 18 6 4 9 16 7 5.5 8 11 8 5 7 14 9 6 6 11 10 5 7 18 Average speed 5.1 7.4 14.6
193 Appendices
Appendix 7. DATA REGARDING REMOVAL OF FUZZ (COTTONY SECRETIONS) FROM THE PUPA ONCE
Dated Males changes 02.04.07 Five pupa fuzz removed 03.04.07 Again repaired fuzz 04.04.07 In pupal form 05.04.07 In pupal form 06.04.07 In pupal form 07.04.07 In pupal form 08.04.07 In pupal form 09.04.07 In pupal form 10.04.07 In pupal form 11.04.07 Two healthy males comes out 12.04.07 Three healthy males comes out
Appendix 8. DATA REGARDING REMOVAL OF FUZZ FROM THE PUPA TWICE A TIME
Dated Males changes 02.04.07 Five pupa fuzz removed 03.04.07 Again repaired fuzz 04.04.07 Removed fuzz again 05.04.07 Again repaired fuzz 06.04.07 In pupal form 07.04.07 In pupal form 08.04.07 In pupal form 09.04.07 In pupal form 10.04.07 In pupal form 11.04.07 One healthy males comes out 12.04.07 Four healthy males comes out
194 Appendices
Appendix 9. DATA REGARDING REMOVAL OF FUZZ FROM THE PUPA THRICE TIME
Dated Males changes 02.04.07 Five pupa fuzz removed 03.04.07 Again repaired fuzz 04.04.07 Removed fuzz again 2 nd times 05.04.07 Again repaired fuzz 06.04.07 Removed fuzz again 3 nd times 07.04.07 Not repaired and dried 08.04.07 Not repaired 09.04.07 Not repaired 10.04.07 Not repaired 11.04.07 No males comes out 12.04.07 No males comes out
195 Appendices
Appendix 10. DATA REGARDING NUMBER OF EGGS LAID BY FEMALES DAILY
Dated Eggs laid daily by female F-1 F-2 F-3 F-4 F-5 18.05.07 0 0 0 0 0 19.05.07 0 0 0 0 0 20.05.07 0 0 0 0 0 21.05.07 0 0 0 0 0 22.05.07 45 0 0 0 0 23.05.07 54 0 0 0 0 24.05.07 56 0 0 0 0 25.05.07 17 26 0 0 0 26.05.07 32 26 29 0 0 27.05.07 40 32 37 0 0 28.05.07 28 33 39 48 0 29.05.07 25 29 30 40 0 30.05.07 22 27 27 34 0 31.05.07 20 32 21 37 25 01.06.07 8 21 21 19 40 02.06.07 2 26 11 28 46 03.06.07 10 11 6 15 30 04.06.07 1 7 0 11 27 05.06.07 1 9 0 11 24 06.06.07 1 4 0 10 24 07.06.07 0 9 0 7 14 08.06.07 0 3 0 3 22 09.06.07 0 2 0 0 17 10.06.07 0 0 0 0 0 11.06.07 0 0 0 0 0 12.06.07 0 0 0 0 0 Total number of eggs laid /female 362 297 221 263 269 Average eggs laid/day 13.9 11.4 8.5 10.1 10.4
196 Appendices
Appendix 11. DATA REGARDING FIRST INSTAR NYMPHS LIVE WITHOUT FOOD
Dated 1st Instar nymphs (Number of nymphs/petridish) Petri dish-1 Petri dish - Petri dish - Petri dish - Petri dish - (7) 2 (15) 3 (18) 4 (19) 5 (5) 18.01.07 0 0 0 0 0 19.01.07 0 0 0 0 0 20.01.07 0 0 0 0 0 21.01.07 0 0 0 0 0 22.01.07 0 0 0 0 0 23.01.07 3 1 5 10 2 24.01.07 0 0 0 0 0 25.01.07 1 2 0 0 0 26.01.07 0 2 0 0 0 27.01.07 0 0 5 3 2 28.01.07 0 0 0 0 1 29.01.07 0 0 1 0 0 30.01.07 1 1 0 1 0 31.01.07 0 1 1 0 0 01.02.07 0 0 1 0 0 02.02.07 0 1 0 0 0 03.02.07 0 1 1 0 0 04.02.07 1 2 3 1 0 05.02.07 0 1 0 2 0 06.02.07 0 2 0 0 0 07.02.07 0 0 0 1 0 08.02.07 1 0 0 0 0 09.02.07 0 0 0 0 0 10.02.07 0 0 0 0 0 11.02.07 0 0 1 0 0 12.02.07 0 0 0 0 0 13.02.07 0 0 0 0 0 14.02.07 0 0 0 1 0 15.02.07 0 0 0 0 0 16.02.07 0 0 0 0 0 17.02.07 0 0 0 0 0 18.02.07 0 0 0 0 0 19.02.07 0 1 0 0 0 20.02.07 0 0 0 0 0 Total died 5-19 days
197 Appendices
Appendix 12. DATA REGARDING SECOND AND THIRD INSTAR NYMPHS LIVE WITHOUT FOOD
Dated 1st Instar nymphs (Number of nymphs/petridish) Petri dish-1 Petri dish - Petri dish - Petri dish - Petri dish - (7) 2 (15) 3 (18) 4 (19) 5 (5) 18.01.07 0 0 0 0 0 19.01.07 0 0 0 0 0 20.01.07 0 0 0 0 0 21.01.07 0 0 0 0 0 22.01.07 0 0 0 0 0 23.01.07 3 1 5 10 2 24.01.07 0 0 0 0 0 25.01.07 1 2 0 0 0 26.01.07 0 2 0 0 0 27.01.07 0 0 5 3 2 28.01.07 0 0 0 0 1 29.01.07 0 0 1 0 0 30.01.07 1 1 0 1 0 31.01.07 0 1 1 0 0 01.02.07 0 0 1 0 0 02.02.07 0 1 0 0 0 03.02.07 0 1 1 0 0 04.02.07 1 2 3 1 0 05.02.07 0 1 0 2 0 06.02.07 0 2 0 0 0 07.02.07 0 0 0 1 0 08.02.07 1 0 0 0 0 09.02.07 0 0 0 0 0 10.02.07 0 0 0 0 0 11.02.07 0 0 1 0 0 12.02.07 0 0 0 0 0 13.02.07 0 0 0 0 0 14.02.07 0 0 0 1 0 15.02.07 0 0 0 0 0 16.02.07 0 0 0 0 0 17.02.07 0 0 0 0 0 18.02.07 0 0 0 0 0 19.02.07 0 1 0 0 0 20.02.07 0 0 0 0 0 Total died 5-19 days
198 Appendices
Appendix 13. DATA REGARDING ADULT FEMALE LIVE WITHOUT FOOD
Dated Adult females (Number of nymphs/petridish) Petri dish-1 Petri dish - Petri dish - Petri dish - Petri dish - (9) 2 (16) 3 (13) 4 (17) 5 (20) 05.03.07 0 0 0 0 0 06.03.07 0 0 0 0 0 07.03.07 0 0 0 0 0 08.03.07 0 0 0 0 0 09.03.07 0 0 0 0 0 10.03.07 0 0 0 0 0 11.03.07 0 0 0 0 0 12.03.07 0 0 0 0 0 13.03.07 0 0 1 0 0 14.03.07 0 0 0 0 0 15.03.07 1 0 0 0 3 16.03.07 0 2 0 0 5 17.03.07 3 1 4 3 2 18.03.07 0 5 0 1 1 19.03.07 2 3 2 5 4 20.03.07 3 2 3 4 0 21.03.07 0 1 3 2 3 22.03.07 0 2 0 1 2 Total died 8-17 days
199 Appendices
Appendix 14. DATA REGARDING TIME TAKEN BY THE MALE S FOR MATING WITH THE FEMALES
Number of males Time taken (Minutes: Seconds) 1 7.00 2 8.30 3 20.50 4 6.00 5 9.25 6 14.30 7 18.20 8 16.10 9 11.30 10 19.10 11 15.30 12 15.30 13 11.00 14 6.30 15 10.00 16 12.30 17 9.00 18 6.45 19 11.15 20 17.50 Average time taken /male 12.2 minute/male
200