Evaluation of Propiconazole
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University of Ghana http://ugspace.ug.edu.gh EVALUATION OF PROPICONAZOLE (TILT) AND PRUNING IN THE CONTROI^OF.jBLACK SIQATOKA DISEASE IN/QHANA 1< \\ y! *( X f r # ■*'... 0SP»s4S ’KWAS'J ZW /tKPU') IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE HEGREEE OF MASTER OF PHILOSOPHY IHCROPSCIEHCE NOVEMBER, 1997 CROP SCIENCE DEPARTMENT UNIVERSITY OF GHANA LEGON University of Ghana http://ugspace.ug.edu.gh University of Ghana http://ugspace.ug.edu.gh DECLARATION I hereby declare that, except for reference to other people's work which have been duly cited, this work is the result of my own original research and that this work has neither in whole nor in part been presented for degree in this University or elsewhere. CEPHAS KWASI BODAKPUI (STUDENT) 2£7 r.F’.Xf DATE DR. K. A. ODURO (SUPERVISOR) DATE PROF. K. -NUAMAH (CO-SUPERVISOR)(CO-SUPERVISOR) DATE i University of Ghana http://ugspace.ug.edu.gh ABSTRACT Pruning of diseased leaves and the use of Propiconazole (Tilt), a foliar fungicide with systemic properties, were two different recommendations made by the Ministry of Food and Agriculture to control black sigatoka, currently an important disease of plantain in the country. The two methods were evaluated from September 1995 to April 1997 at the University of Ghana Agriculture Research Station, Kade. Four treatments, namely, Tilt (0.125g ai/L), Pruning, Tilt (0.125g ai/L) + Pruning and Control (neither Tilt nor Pruning), were applied in; an RCBD experiment. The average height of the plantain in the different treatments were found not to be significantly different from each other. Using percentage total leaf area attacked, disease severity for the Control treatment was on the average 16% (13.1-19%) while it was 4.6% (2.6- 6.2%),5.1% (3.7-6.4%) and 3.8% (2.5-5.0%) for Tilt, Pruning and Tilt+Pruning respectively. The Control was significantly different from the other three treatments which were, however, not different from each other at 5% significance level. Maturity of plantain was found to delay in the Control. The total number of bunches harvested at 66 weeks were 54, 50, 52 and 47 with bunch weights of i i University of Ghana http://ugspace.ug.edu.gh 453.OKg, 3 9 2 .2Kg, 405.OKg and 249.lKg for Tilt, Pruning, Tilt+Pruning and Control respectively. The Control was significantly different from the other three treatments which were however not different from each other (p. 5%). The difference in bunch weight was due to significant difference in weight per finger (0.258Kg, 0.245Kg, 0.252Kg and 0.186Kg), respectively, for the treatments. There was no difference in the number of fingers per bunch which was on the average 26.1 for all the treatments. Correlation analysis gave a negative but a significant association (r = -0.96) between severity of disease and yield. Simple pruning and burning of diseased leaves could be recommended for the control of black Sigatoka in the absence of chemical which may be expensive. To determine the potency of the chemical (Tilt), a bioassay was conducted in the laboratory. One ml of the following concentrations of Tilt viz. 0.0125g ai/L; 0.025g ai/L; 0.05g ai/L 0.0625g ai/L and 0.075g ai/L were incorporated into 5 different PDA in Petri dishes to form Tilt-ammended PDA media plus a control (only PDA). Ascospores from diseased leaves were ejected onto these plates. Germination in all cases started about 12 hours after ejection. Unipolar and bipolar germ tubes Were observed on all the plates but the percentages differ, depending on the concentration of Tilt. The higher the i i i University of Ghana http://ugspace.ug.edu.gh concentration, the lower the percentage germination. Visible growth was seen with the naked eye after 4 days. Aerial mycelia was whitish with reverse dark on the control plates while the aerial mycelia on Tilt-ammended PDA were gray with reverse dark. No conidia were seen in all cases after several weeks. The bioassay studies confirmed that Tilt was potent. i v University of Ghana http://ugspace.ug.edu.gh ACKNOWLEDGEMENT I with to express my profound gratitude to Dr. K. A. Oduro - Head of Crop Science Department, University of Ghana, Legon and Prof. K. Afreh-Nuamah - University of Ghana Agricultural Research Station (UGARS)- Kade under whose excellent supervision I wrote this thesis. Their constructive criticism, patience and encouragement made this work a reality. I am indebted to Dr. K. G. Ofosu-Budu and Dr. J. K. Osei both of UGARS-Kade who freely volunteered information during the course of the project. I am also indebted to Mr. A. Ampomah and Mr. J. M. Kokroh - Farm manager and senior Assistant farm manager respectively, at UGARS-Kade, for their valuable help and contributions from the beginning to the end of the field work. I am grateful to Mr. Ayifa and wife, Sister Lydia Larbi, and the workers of UGARS-Kade, for their immense assistance whenever I went there. My sincere thanks go to my course mates especially Messrs. Michael Assuah, Edmund Botchway, Gershon Wodzrah and Benard Boateng for their good company and encouragement during my stay at University of Ghana. Finally, I thank Miss Favour Anyam who typed the script. To all who helped in one way or the other, I say, thank you. May the Almighty God bless you. v University of Ghana http://ugspace.ug.edu.gh DEDICATION This work is dedicated to my wife, MRS. JOSEPHINE BODAKPUI, and my son, MARIUS EDEM FIIFI BODAKPUI. v i University of Ghana http://ugspace.ug.edu.gh TART.K OF CONTENT CONTENT DECLARATION........................................... i ABSTRACT..............................................ii ACKNOWLEDGEMENT....................................... V DEDICATION............................................vi CHAPTER ONE : INTRODUCTION............................. 1 CHAPTER TWO: LITERATURE REVIEW........................ 4 2.1 Origin and importance........................... 4 2.2 The Pathogen.................................... 5 2.2.1 The Conidia stage............................ 6 2.2.2 The Perfect or Ascospore stage............... 6 2.3 Disease development and symptoms................7 2.4 Control......................................... 8 2.4.1 Cultural...................................... 8 2.4.2 Genetic improvement........................... 9 2.4.3 Chemical control.............................. 10 2.5 Propiconazole.................................. 14 CHAPTER THREE: MATERIALS AND METHODS..................16 3.1 Fieldwork...................................... 16 3.1.1 Project site.................................. 16 3.1.2 Land preparation and treatments...............16 3.1.3 Planting material and planting................17 3.1.4 Research activities and records taken........ 17 v i i University of Ghana http://ugspace.ug.edu.gh 3.2 Bioassay studies in the laboratory..............22 3.2.1 Media Preparation............................. 22 3.2.2 Isolation of pathogen......................... 23 3.2.3 Data collected................................ 24 CHAPTER FOUR: RESULTS................................. 25 4.1 Fieldwork...................................... 25 4.1.1 Effect of the treatments on plant height of plantain .................... 25 4.1.2 Effect of Tilt and Pruning on average number of leaves of plantain infected by black Sigatoka.................................... .25 4.1.3 Effect of Tilt, Pruning and amount of rainfall on severity of black Sigatoka....... 28 4.1.4 Effect of Tilt and Pruning on yield of plantain..................................... 32 4.2 Bioassay in the laboratory for testing efficacy of the chemical (Tilt).......................... 38 4.2.1 Ascospore discharge........................... 38 4.2.2 Ascospore germination......................... 38 4.2.3 Culture characteristics....................... 43 CHAPTER FIVE: DISCUSSIONS............................. 48 5.1 Effect of Tilt and Pruning on height of plantain.......................................48 5.2 Effect of Tilt, Pruning and amount of rainfall on severity of black Sigatoka and yield of plantain at Kade............................... 49 v i i i University of Ghana http://ugspace.ug.edu.gh 5.3 Efficacy of Tilt as evidenced in the Bioassay studies........................................ 52 CHAPTER SIX: CONCLUSIONS AND RECOMMENDATIONS..........54 CHAPTER SEVEN: LITERATURE CITED..................... 55 APPENDICES:........................... 63 APPENDIX I ANOVA table for average number of leaves 28 to 44 weeks after planting. .63 APPENDIX II ANOVA table for youngest leaf with symptom (YLWS) 28 to 44 weeks after planting.............................. 64 APPENDIX III ANOVA table for average bunch weight...66 APPENDIX IV ANOVA table for average number of fingers per bunch..................... 66 APPENDIX V ANOVA table for length of "middle" finger................................ 67 APPENDIX VI ANOVA table for weight of "middle" finger................................ 67 APPENDIX VII ANOVA table for disease severity from week 8 to week 44...... 67 i x University of Ghana http://ugspace.ug.edu.gh T.TST OF FIGURES FIGURE TITLE PAGE 1. Spraying Tilt 250EC with knapsack sprayer on short plantain plants infected by black Sigatoka disease................................ 20 2. Spraying Tilt 250EC with motorised mist blower on tall plantain plants infected by black Sigatoka disease................................ 21 3. Average plant height of plantain infected by black Sigatoka disease.......................... 26 4. Effect of Tilt, Pruning and amount of rainfall on black Sigatoka............................... 29 5. Effect of Tilt and Pruning on black