OCCURRENCE OF ARTHROPOD PESTS OF TOMATO AND
EFFICACY OF ENTOMOPATHOGENIC FUNGI
AGAINST Frankliniella occidentalis (Pergande) IN BUNGOMA
COUNTY, KENYA
BARASA WABUKALA MICHAEL [BSc. Agric]
A145/38309/2016
A thesis submitted in partial fulfillment of the requirements for the degree
of Master of Science in Crop Protection (Entomology option),
Department of Agricultural Science and Technology,
Kenyatta University
June, 2020
ii
DEDICATION
I dedicate this thesis to my uncle Francis Mwotei, my mother Hellen Chepyos
Barasa and my father Patrick Barasa Waliaula for their presence and guidance in my life.
iii
ACKNOWLEDGEMENTS
Special and heartfelt thanks go to my supervisors, Dr. Ruth Kahuthia-Gathu and Prof. Maina Mwangi of Kenyatta University for their relentless support, judicious guidance, encouragement, profound advice and dedicating their time for mentoring me during the period of this study and writing of thesis. I am greatly thankful to the management of Osho Chemical Industries Limited for funding this study under the project “Bio-prospecting for potential biocontrol agents in Kenya and Capacity Building in Crop Protection”. Special appreciation goes to the management of Kenyatta University for providing the research facilities without which, this work could not have been possible. I appreciate the Principal investigator Prof. Waceke Wanjohi for her guidance, motivation and mechanisms dedicated to ensure availability of funds on time for the entire study. I also express gratitude to Ms. Njeri Njau for her profound assistance and inspiration. My sincere thanks go to Dr. Everlyne Samita for her encouragement and moral support during the study. Mr. Fulano Alex, I acknowledge you for your motivation and support during the development of my proposal. I am greatful to the laboratory technicians Ms. Lucy Wangu, Ms.
Kallen Gacheri and Ms. Rachael Wanjiru, for your assistance. My appreciation goes to Mr. Francis Mwotei and Mr. Julius Mbito who offered me excellent fields for the experiments in Mt. Elgon, Bungoma County and my field assistants Mr. Moses Chepkech and Mr. Benard Kiso. I acknowledge my parents and siblings for their prayers and support. Finally, I thank the Almighty
God for the wisdom, knowledge and guidance throughout the entire period of my studies.
iv
LIST OF ABBREVIATIONS AND ACRONYMS
ANOVA Analysis of variance
ASL Above Sea Level
BML Bumula
Bt Bacillus thuringiensis
CAN Calcium Ammonium Nitrate
CIDP County Integrated Development Plan
CRD Completely Randomized Design df Degrees of freedom
F: Statistical F-value
FAO Food and Agriculture Organization of the united Nations
FAOSTAT Food and Agriculture Organization Statistics
GPS Global Positioning System
Ha Hectare
HCDA Horticultural Crops Development Authority
IPM Integrated Pest Management
KU Kenyatta University
LH Lower Highland
LM Lower Midland
ME Mt. Elgon
MRLs Maximum Residue Levels
NAFIS National Farmers Information Service
NICRA National Initiative on Climate Resilient Agriculture
v
NPK Nitrogen Phosphate Potassium
P: Probability value for error level
PDA Potato Dextrose Agar
RCBD Randomized complete block design
RH Relative Humidity
RTFI Route to Food Initiative
SAS Statistical Analysis Software
SE Standard error ofv the mean
SNK Student Newman-Keuls test sp. Species
SPSS Statistical Package for Social Sciences
SRS Sirisia
TCSV Tomato Chlorotic Spot Virus
TSWV Tomato Spotted Wilt Virus
TYLCV Tomato Yellow Leaf Curl Virus
URT United Republic of Tanzania
USA United States of America var. Variety
WAT Weeks after transplanting
vi
TABLE OF CONTENTS
DECLARATION ...... i
DEDICATION ...... ii
ACKNOWLEDGEMENTS ...... iv
LIST OF ABBREVIATIONS AND ACRONYMS ...... v
TABLE OF CONTENTS ...... vii
LIST OF TABLES ...... xi
LIST OF FIGURES ...... xii
LIST OF PLATES ...... xiii
ABSTRACT ...... xiv
CHAPTER ONE: INTRODUCTION...... 1
1.1 Background information ...... 1
1.2 Statement of the problem ...... 3
1.3 Justification of the study ...... 4
1.4 Research objectives ...... 6
1.4.1 General objective ...... 6
1.4.2 Specific objectives ...... 6
1.5 Hypotheses ...... 7
1.6 Conceptual framework...... 8
CHAPTER TWO: LITERATURE REVIEW ...... 10
2.1 Origin and cultivation of tomato...... 10
2.2 Economic and nutritional value of tomato...... 11
2.3 Tomato production in Kenya ...... 12
vii
2.4 Economically important arthropod pests of tomatoes ...... 13
2.4.1 Damage caused by arthropod pests of tomato ...... 13
2.4.2 Management of arthropod pests of tomato ...... 16
2.5 Diseases affecting tomato production ...... 20
2.6 Use of entomopathogenic fungi in crop protection ...... 22
2.7 Mechanism of suppression by entomopathogenic fungi against arthropod
pests ...... 23
2.8 Methods of application of entomopathogenic fungi in in-vitro bioassays ...... 24
CHAPTER THREE: MATERIALS AND METHODS ...... 26
3.1 Determination of occurrence of major arthropod pests of S. lycopersicum
in Bungoma County, Kenya...... 26
3.1.1 Description of study areas ...... 26
3.1.2 Determination of tomato production practices ...... 27
3.1.3 Assessment of occurrence of major arthropod pests of tomato ...... 28
3.2 Evaluation of insecticidal activity of antagonistic fungi in biological
control of Western flower thrips in vitro ...... 29
3.2.1 Sources of fungal antagonists ...... 29
3.2.2 Preparation of culture ...... 29
3.2.3 Isolation of antagonistic micro-organisms...... 30
3.2.4 Purification, identification and storage of fungal antagonists ...... 30
3.2.5 Collection and maintenance of Western flower thrips Frankliniella
occidentalis ...... 31
3.2.6 Preparation of conidial suspensions for in vitro bioassay ...... 32
3.2.7 Screening of fungal isolates against Frankliniella occidentalis in vitro ...... 32
viii
3.3 Determination of the effectiveness of fungal antagonists in management
of Frankliniella occidentalis under field conditions ...... 33
3.3.1 Description of experimental site ...... 33
3.3.2 Mass production of antagonistic fungi and preparation of inoculum ...... 34
3.3.3 Field experiment layout, design and data collection ...... 35
3.4 Data analysis ...... 38
CHAPTER FOUR: RESULTS ...... 39
4.1 Occurrence of major arthropod pests of tomato in Bungoma County ...... 39
4.1.1 Tomato production characteristics ...... 39
4.1.2 Occurrence of arthropod pests and diseases of tomato in Bungoma County ...... 43
4.1.3 Management of pests and diseases of tomato in Bungoma County ...... 45
4.1.4 Chemical application practices on management of tomato pests in
Bungoma County ...... 47
4.1.5 Farmers’ sources of information on the use of chemicals in controlling
tomato pests and diseases in Bungoma County ...... 48
4.2 Evaluation of insecticidal activity of antagonistic fungi in biological
control of Frankliniella occidentalis in vitro ...... 49
4.2.1 Entomopathogenic fungi isolated from soil ...... 49
4.2.2 Efficacy of fungal isolates against F. occidentalis in vitro ...... 51
4.3. Effectiveness of fungal antagonists in management of F. occidentalis...... 54
on tomatoes in the field ...... 54
CHAPTER FIVE: DISCUSSION ...... 67
5.1 Occurrence of major arthropod pests of tomato in Bungoma County ...... 67
5.1.1 Demographic characteristics of tomato farmers ...... 67
ix
5.1.2 Tomato varieties grown by farmers in Bungoma County ...... 68
5.1.3 Arthropod pests and diseases affecting tomato production in Bungoma
County ...... 69
5.1.4 Management of arthropod pests and diseases of tomato in Bungoma
County ...... 69
5.2 Evaluation of insecticidal activity of antagonistic fungi in biological
control of F. occidentalis in vitro ...... 71
5.3. Effects of fungal antagonists on management of F. occidentalis on
tomato ...... 71
CHAPTER SIX: CONCLUSIONS AND RECOMMENDATIONS ...... 75
6.1: Conclusions ...... 75
6.2: Recommendations ...... 75
APPENDICES ...... 104
x
LIST OF TABLES
Table 4.1: Gender, age and the education level of tomato growers in ...... 40
Table 4.2: Farmers’ experience in tomato production in Bungoma County .... 42
Table 4.3: Chemicals used by farmers in management of tomato pests in
Bungoma County ...... 46
Table 4.4: Chemicals used by farmers in the control of diseases on tomato .... 47
Table 4.5: Chemical application practices on tomato production in
Bungoma County ...... 48
Table 4.6: Most available sources of agricultural information on tomato
production in Bungoma County ...... 49
Table 4.7: Fungal species tested against F. occidentalis and their origin ...... 50
Table 4.8: Efficacy of fungal isolates against F. occidentalis in vitro...... 52
Table 4.9: Mean number ± S.E of F. occidentalis per flower on tomato
treated by different fungal species...... 57
Table 4.10: Mean number ± S.E of F. occidentalis per flower on tomato
recorded at Cheptais...... 61
Table 4.11: Mean yield (t/ha) ± S.E of tomatoes harvested at Bukonoi
during the long rainy season (March-July, 2018)...... 62
Table 4.12: Mean yield (t/ha) ± S.E of tomatoes harvested at Bukonoi
during short rainy season (August-November, 2018)...... 63
Table 4.13: Mean yield (t/ha) ± S.E of tomatoes harvested at Cheptais in
long rainy season (March-July, 2018)...... 64
Table 4.14: Mean yield (t/ha) ± S.E of tomatoes harvested at Cheptais in
short rainy season (August-November, 2018)...... 65
xi
LIST OF FIGURES
Figure 1.1: Conceptual framework on the use of fungal antagonists in
management of tomato pests ...... 9
Figure 3.1:Map of Bungoma County showing the surveyed Sub-Counties
(Mt. Elgon, Sirisia and Bumula)...... 27
Figure 4.1: Farm sizes of tomato farmers in Bungoma County ...... 41
Figure 4.2: Tomato varieties grown by respondents in Bungoma County ...... 42
Figure 4.3: Arthropod pests of tomato in Bungoma County ...... 44
Figure 4.4: Diseases affecting tomato production in Bungoma County ...... 45
Figure 4.5: Trend of Western flower thrips in tomatoes under different
fungal treatments during long rainy cropping season at
Bukonoi...... 55
Figure 4.6: Trend of Western flower thrips in tomatoes under different
fungal treatments during short rainy cropping season at
Bukonoi...... 56
Figure 4.7: Trend of Western flower thrips in tomatoes under different
fungal treatments during long rainy cropping season at
Cheptais...... 58
Figure 4.8: Trend of Western flower thrips in tomatoes under different
fungal treatments during short rainy cropping season at
Cheptais...... 59
xii
LIST OF PLATES
Plate 4.1: Major pests identified infesting tomatoes in Bungoma County;
A: F. occidentalis B: T. absoluta, C: M. persicae, D: B. tabaci.
(X10 Mg) ...... 43
Plate 4.2: Isolated fungal antagonists in vitro bioassay; a): Trichoderma.
virens 1, b): Trichoderma virens 2, c): Fusarium solani d)
Fusarium oxysporum...... 53
Plate 4.3: Infection by antagonistic fungus on thrip's cuticle; A:
Trichoderma. afroharzianum, B: Trichoderma virens. (X 40
Mg)...... 53
Plate 4.4: Tomatoes sprayed with fungal antagonists in the field trial A)
Control (water), B) T. afroharzianum, C) F. oxysporum, D) B.
bassiana (Commercial), E) T. virens 2., F) Imidacloprid
(synthetic pesticide)...... 66
xiii
ABSTRACT Tomato Solanum lycopersicum L. is an important crop in Kenya. Arthropod pests are major constraints to its production. The pests make farmers to rely heavily on synthetic chemicals for control and this increases costs and pollution of the environment. The objective of this study was to assess the occurrence of arthropod pests of tomato and evaluate the effectiveness of native Kenyan fungi in managing thrips as an alternative to synthetic pesticides. A survey was carried out in Bungoma County and data collected from ninety farmers on tomato production practices, pests present, diseases and their management practices. In vitro studies were conducted to evaluate the effectiveness of native fungi against Frankliniella occidentalis collected from the tomato fields and maintained in the laboratory. The fungi were isolated from ninety soil samples from tomato fields and identified based on their vegetative and reproductive structures. Treatments included fungal isolates and a control; replicated four times arranged in a completely randomized design. The effect of the fungal isolates on F. occidentalis was evaluated by treating thrips with concentrations of 1.0 x107conidia ml-1. Data on mortality of F. occidentalis was recorded daily for 10 days after treatment. Field trials were conducted at Bukonoi and Cheptais in 2018 to determine the most virulent fungal antagonists. The fungi were Trichoderma virens 1, Trichoderma virens 2, Trichoderma afroharzianium, Fusarium solani and Fusarium oxysporum. Their efficacy was compared to Beauveria bassiana, synthetic pesticide Imidacloprid and a control (water). All treatments were applied weekly as foliar sprays commencing three weeks after transplanting of tomatoes until harvesting. Fungal antagonists were applied at a rate of 1.0 x108 cfu g-1. Treatments were replicated four times in a randomized complete block design. Data were collected on population of F. occidentalis and the yield. Survey data was analyzed using SPSS version 18.0 while data on in vitro and field trials were subjected to Analysis of Variance using SAS version 9.4. Means were separated using Student Newman-Keuls test at P≤0.05. Results revealed F. occidentalis (58.6%) as major pests of tomato and Ralstonia solanacearum disease (75%). The most frequently used chemicals were Imidacloprid (24.4%) and Mancozeb (17.2%). Only 2.4% of the growers used bio-pesticides. In vitro studies showed that T. virens, F. solani, F. oxysporum and T. afroharzianum were more virulent against F. occidentalis causing mortalities above 50%. The least mean number of F. occidentalis per flower at Bukonoi was observed on T. afroharzianum and F. oxysporum treated plots with 2.2 and 1.0 during long and short rainy season, respectively. At Cheptais, the lowest mean of F. occidentalis (2.4) was recorded on F. oxysporum and T. afroharzaianum (1.0), respectively. Tomato plots treated with T. afroharzianum gave the highest yield of 3.8 t/ha and 27.2 t/ha during the long and short rainy season at Bukonoi with a corresponding 0.3 t/ha and 12.3 t/ha at Cheptais, respectively. The findings showed that T. afroharzianium and F. oxysporum have potential for development as fungal-based bio-pesticides against F. occidentalis on tomato. Further studies should be done to determine the optimal conditions for effectiveness of F. oxysporum and T. afroharzianum.
xiv
CHAPTER ONE: INTRODUCTION 1.1 Background information
Tomato Solanum lycopersicum L. is native to South and Central
America and belongs to the family Solanaceae (Infonet-biovision, 2019). The crop is among the most extensively cultivated vegetables globally (Mattoo and
Hanada, 2017). Tomato is grown for its fruits which are cooked as a vegetable or used in salads and it is an important source of vitamins A and C (Chaudhary et al., 2018; Infonet-biovision, 2019). The three major tomato producing countries in the world are China, India and United States of America. Other key countries producing tomatoes are Turkey, Egypt, Iran, Italy, Spain, Brazil,
Mexico, Russia and Uzbekistan (FAO, 2018).
In Kenya, tomato is the most popular consumed exotic vegetable accounting for 38.1% by value of the exotic vegetables (HCDA, 2018). It also contributes about 19.9 billion Kenya shillings annually to the economy and provides income and employment opportunities to small scale farmers (HCDA,
2018). Tomato production is estimated to be an average of 283,000 tonnes per annum (FAO, 2018). The leading tomato producing Counties include
Kirinyaga (17%), Kajiado (11.8%), Taita Taveta (8.5%), Laikipia (7.2%) and
Bungoma (7.0%) (HCDA, 2018; NAFIS, 2018).
Tomato is mostly grown in open fields under irrigation or rainfed but also in greenhouses (Monsanto, 2017; Ireri et al., 2018). The open field varieties include Riogrande, Rambo F1, Cal-J, Onyx F1, Faulu, Oxly, Joy F1,
New Fortune maker F1, Libra F1, Kentom F1, Sandokan F1 and Strike F1,
1 while Prostar F1, Chonto F1, Anna F1, Bravo, Harmony F1, Monalisa F1 and
Samantha F1are grown under greenhouse conditions (Monsanto, 2017).
Arthropod pests and diseases are the main drawbacks to sustainable tomato production (Singh et al., 2014; HCDA, 2018; Ochilo et al., 2018). The major arthropod pests infesting tomatoes are the leaf miner moth Tuta absoluta
(Meyrick) (Lepidoptera: Gelichiidae), Western flower thrips Frankiliniella occidentalis Pergande (Thysanoptera: Thripidae), whitefly Bemisia tabaci
Gennadius (Homoptera: Aleyrodidae), leaf miner fly Liriomyza spp. (Diptera:
Agromizydae), red spider mite Tetranychus evansi Baker (Acari:
Tetranychidae) and African bollworm Helicoverpa armigera (Hubner)
(Lepidoptera: Noctuidae) (Gacheri, 2016; Wakil et al., 2018; Infonet-biovision,
2019).
Smallholder tomato farmers in Kenya rely heavily on synthetic pesticides to manage the complex of economically important arthropod pests
(Asante et al., 2013; Ochilo et al., 2018). However, inappropriate use and continuous application of pesticides leads to build up of residues, environmental pollution, development of resistance to pesticides and elimination of beneficial organisms (Ndakidemi et al., 2016; Chung, 2018;
Rashidi and Ganbalani, 2018). The negative impacts of pesticides have increased an interest to develop environmentally safe and sustainable strategies to manage arthropod pests.
There has been a focus on the use of biopesticides as an alternative to synthetic chemicals in management of important arthropod pests (Srijita,
2015). Biopesticides have minimal toxic residues, are safe to non-target
2 organisms and can be affordable to farmers if produced locally (Gupta et al.,
2014; Ouma et al., 2014). This study aimed at evaluating the effectiveness of entomopathogenic fungi from the local soil environment in the management of major arthropod pests of tomato.
1.2 Statement of the problem
According to studies, tomato is infested by a complex of arthropod pests that include T. absoluta, F. occidentalis, B. tabaci, Liriomyza spp.,
Tetranychus spp. and H. armigera from the time of emergence to harvesting
(Infonet-biovision, 2019). Lack of adequate knowledge by tomato growers makes them rely heavily on the use of synthetic pesticides as the most convenient and effective way of managing arthropod pests of tomatoes
(Karuku et al., 2016; Nguetti et al., 2018; Barasa et al., 2019). In addition, tomato farmers do not adhere to the required pre-harvest intervals, handling requirements and application rates of synthetic pesticides to manage pests
(Mwangi et al., 2015; Ochilo et al., 2018).
Synthetic pesticides are fast acting, have long residual effects and are more effective in controlling insect pests of crops (Bhattacharjee and Dey,
2014). However, frequent use of synthetic pesticides leads to pollution of the environment, contamination of the produce with pesticide residues, causes detrimental effect to non-target beneficial organisms, are harmful to applicants and results in development of resistance among the pests (Ndakidemi et al.,
2016; Rashidi and Ganbalani, 2018; Nguetti, 2019).
3
Recent studies have revealed the presence of pesticide residues above the Maximum Residue Levels (MRLs) in fresh tomatoes produced and marketed in Kenya (Kithure et al., 2014; Nguetti, 2019). The different kinds of synthetic chemicals found in the produce include dithane 45, ridomil, antracol, karate, bestox, milraz and cyclone. Among them are still some active ingredients in synthetic chemicals which have been restricted for use in fruits and vegetables as they are carcinogenic, mutagenic, endocrine disrupter, neurotoxic and show clear effects on the human reproduction (RTFI, 2019).
These include imidacloprid, thiamethoxam, acephate and carbendazim and mancozeb (Bollmohr and Liebetrau, 2019).
The increasing demand of tomatoes by the growing target domestic consumers, processors, supermarkets and exporters from Kenya have created the need to set stringent quality standards that require the tomatoes to be free from pesticide residues and clean for human consumption (Engindeniz and
Ozturk, 2013; Wagnitz, 2014; Nguetti et al., 2019) hence the need to find safer, affordable and sustainable alternatives to synthetic pesticides.
1.3 Justification of the study
Tomato is an important crop in Kenya mostly grown by small-scale farmers in rural areas and peri-urban regions. Bungoma County is among the key tomato producing regions in Kenya dominated by small-scale farmers
(HCDA, 2018; NAFIS, 2018). Despite the economic benefits of tomato as a source of income, food and employment opportunities, arthropod pests remain the major limitations to its production resulting in reduced yields and poor
4 quality of the produce (Sabbour, 2014, Ochilo et al., 2018). Synthetic pesticides are heavily used by farmers as the main strategy for the management of the major arthropod pests of crops (Bhattacharjee and Dey, 2014).
Satisfying the needs of the consumers, human health and safety of the environment can be realized by the use of biopesticides as alternative pest management products (Engindeniz et al., 2013; Bollmohr and Liebetrau, 2019).
There has been an increasing practical focus on the use of microbial bio- pesticides as alternative to synthetic chemical pest control products (Srijita,
2015; Fulano, 2016; Muthomi et al., 2017) as they do not result in toxic pesticide residues in the produce, are very effective in the long term, have multiple modes of action on arthropod pests, are target specific, safer to the environment, humans, natural enemies of arthropod pests such as predators and parasitoids and can be cheaper than the synthetic pesticides especially if locally produced (Gupta et al., 2014; Sola et al., 2014; Ndereyimana et al., 2019).).
Microbial biopesticides have been used to manage pests and diseases in other crops and losses have hence been minimized (Shafie and Abdelraheem, 2012;
Fulano, 2016; Lengai, 2016).
Majority of the commercial microbial biopesticides available in Kenya are imported (Infonet-biovision, 2019). In our environment there are also microbes such as entomopathogenic fungi which are found in the imported formulations of the biopesticides and if they could be exploited, there would be minimized risks of importing organisms which could be of phytosanitary harm to our environment (Chethana et al., 2012). Entomopathogenic fungi are
5 naturally occurring and can be exploited from our local environment to make safe products for management of insect pests (Chethana et al., 2012).
As a new technology, the use of locally produced microbial biopesticides will reduce the costs of importing commercial biopesticides, reduce production costs of crop production associated with the frequent use of synthetic pesticides as well as presenting premium value tomatoes on the growing domestic niche markets. This will also enable the farmers find worth in investing in crop production (Kimani, 2014; Ouma et al., 2014).
The use of native Kenyan entomopathogenic fungi as biopesticides has not been fully evaluated. Therefore, this study aimed at evaluating the effectiveness of local isolates of entomopathogenic fungi in managing thrips on tomato as a substitute to the use of synthetic chemicals.
1.4 Research objectives
1.4.1 General objective
To determine the occurrence of major arthropod pests of tomato S. lycopersicum and evaluate the effectiveness of entomopathogenic fungi in the management of F. occidentalis in Bungoma County, Kenya.
1.4.2 Specific objectives
i. To determine the occurrence of major arthropod pests of S.
lycopersicum in Bungoma County, Kenya.
ii. To determine the insecticidal activity of selected fungal isolates
against F. occidentalis of S. lycopersicum in vitro.
6
iii. To evaluate the effectiveness of locally isolated entomopathogenic
fungi in management of F. occidentalis in the field.
1.5 Hypotheses
i. A complex of arthropod pests affects S. lycopersicum production in
Bungoma County, Kenya.
ii. Selected fungal isolates have insecticidal activity against F. occidentalis
of S. lycopersicum in vitro.
iii. Locally isolated antagonistic fungi are effective in the management of
F. occidentalis of S. lycopersicum in the field.
7
1.6 Conceptual framework
Arthropod pests are a major constraint to tomato production in the study areas leading to low yields, poor quality and income. This makes farmers rely heavily on synthetic chemicals to control the pests. However, frequent application of synthetic chemicals leads to pollution of the environment, pesticide residues, pesticide resistance, increased threat to non-target organisms and increased cost of production (Figure 1.1). To enhance sustainable environment friendly pest management strategies, affordable alternatives to synthetic chemicals are necessary. The use of fungal-based microbial pesticides has gained a global interest.
8
High prevalence of arthropod pests Frequent use of synthetic chemicals to control arthropod pests
Research problem
Low yields, poor quality High pesticide residues, pollution of
produce, low income environment, increased production cost, pesticide resistance, increased threat to non-target organisms
Use of fungal antagonists in Intervention management of arthropod pests
Low pest population, increased yields, increased income, reduced pesticide residues, minimal environmental pollution, reduced production costs as fungal antagonists occur naturally resulting in Research outputs affordable prices compared to chemical pesticides whose manufacturing costs are high, reduced pesticide resistance, increased bio-diversity, reduced threat to non-target organisms
Figure 1.1: Conceptual framework on the use of fungal antagonists in management of tomato pests
9
CHAPTER TWO: LITERATURE REVIEW
2.1 Origin and cultivation of tomato
Tomato Solanum lycopersicum L., belongs to the Solanaceae family which consists of other recognized species including eggplant Solanum melongena L., (Solanaceae), pepper Capsicum annum L., (Solanaceae), tobacco Nicotiana tabacum L., (Solanaceae) and potato Solanum tuberosum L.,
(Solanaceae) (Payal et al., 2019). The crop originated from South America and was later introduced in Europe by the Spanish during the sixteenth century where it was spread to the Middle East, Africa, Southern and Eastern Asia
(Gacheri, 2016).
Tomato grows well in relatively warm climatic conditions for high yield and premium quality. It can also be grown in cold climate under protection. Maturity of the crop ranges between 3 and 4 months depending on the cultivar. Sandy loam or clay-loam soils rich in humus are ideal for cultivation of tomato (Fentik, 2017). The optimum temperature range for growth and development is between 21 and 240C. The crop requires soil pH between 6 and 6.5. Increased or decreased soil pH is detrimental to the crop and can lead to mineral deficiency. Frequent flooding delays the growth and development of the crop (Infonet-biovision, 2019).
Tomatoes are categorized into different varieties depending on cultivation method, shape, weight, size and colour. Determinate varieties are commonly adapted in the open field and are most preferred by commercial producers who are interested in canning. The indeterminate varieties are cultivated under green house (Monsanto, 2017; Kanyua, 2018).
10
2.2 Economic and nutritional value of tomato
Tomato is cultivated and consumed worldwide. The crop is eaten fresh in salads, stewed or served as a boiled vegetable. It is also used in preparation of several dishes as well as making of salsa (sauce). Additionally, tomatoes are also processed into products such as tomato juice, ketchup, paste, puree or canned (HCDA, 2018; Infonet-biovision, 2019).
Tomato is nutritious and provides essential quantities of vitamins A and
C (Viuda-Martos et al., 2014; Infonet-biovision, 2019). Vitamin A is essential for cell division, growth of the bones and nourishing the external coating of eyes and differentiation for immune system regulation, intestinal tracts, urinary and respiratory systems. Vitamin C is essential in collagen formation, a protein which provides shape to the muscles, cartilage and blood vessels. It also enhances the absorption of iron which is vital in the formation of red blood cells in the body. Tomato contains 95% water and therefore used as diuretics assisting in elimination of toxins from the body (Hackshaw-McGeagh et al.,
2015).
Tomatoes possess minerals such as phosphorus, potassium, iron, magnesium and calcium that are essential dietary requirements to humans.
Potassium aids in evading the risk of high blood pressure, heart diseases and aids in contraction of muscles. It also reduces the risks of kidney stones and loss of bones, blood clotting and inflammation (Marti et al., 2018). Tomato contains natural antioxidant compounds such as lycopene, which impart the red color of tomatoes. Lycopene in cooked tomatoes have been found to reduce risks of prostate cancer and breast cancer (Hazewindus et al., 2014; Fentik,
11
2017; Chaudhary et al., 2018). Lycopene has also been revealed to increase the ability of the skin to defend against exposure to dangerous ultraviolet radiation, function of the heart and improved vision (Espinosa-Juarez et al., 2017; Merve et al., 2017).
2.3 Tomato production in Kenya
Tomato Solanum lycopersicum L., is the most important staple vegetable crop in Kenya followed by Brassicas (HCDA, 2018). It is an important horticultural crop for meeting nutritional requirement, generating income and employment opportunities for small scale farmers in Kenya
(Asante et al., 2013; Sigei et al., 2014). Tomato production contributes 38.1% of the total vegetable production and 7% of the horticultural production (FAO,
2018). The crop is mainly grown in Kirinyaga, Kajiado, Taita Taveta, Laikipia,
Bungoma, Trans-Nzoia, Narok, Nakuru, Kisumu, Homabay, Machakos,
Kiambu and Meru Counties (HCDA, 2018; Ochilo et al., 2018).
Production of tomato is carried out in the open field and under greenhouse systems (Monsanto, 2017). Riogrande, Rambo F1, Cal-JVF, Onyx
F1, Faulu, Oxly, Joy F1, New Fortune maker F1, Libra F1, Kentom F1,
Sandokan F1 and Strike F1 are tomato varieties adapted in the open field.
Prostar F1, Chonto F1, Anna F1, Bravo, Harmony F1, MonaLisa F1 and
Samantha F1 are grown under greenhouse conditions (Monsanto, 2017; Ochilo et al., 2018).
Production of the crop faces many challenges ranging from biotic to abiotic factors. These include lack of adequate knowledge in tomato
12 production, inadequate capital and post-harvest losses among others. Arthropod pests are the main constraints to tomato production in Kenya (Toroitich et al.,
2014; Wright et al., 2016).
2.4 Economically important arthropod pests of tomatoes
A complex of arthropod pests infests all the growth and development stages of tomato crop. Major below ground arthropod pests include the cut worms Agrotis spp. (Lepidoptera: Noctuidae), that damage the tomato seedlings by cutting off. Additionally, root-knot nematodes Meloidogyne spp. also causes serious damage to tomatoes (Bikash, 2013; Karuku et al., 2016;
Infonet-biovision, 2019). Foliage feeding arthropod pests include leaf miner moth Tuta absoluta (Meyrick) (Lepidoptera: Gelichiidae), red spider mite
Tetranychus evansi Baker (Acari: Tetranychidae), whitefly Bemisia tabaci
Gennadius (Homoptera: Aleyrodidae), and African bollworm Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), aphids Aphis gossypii (Glover)
(Homoptera: Aphididae), Thrips Thrips tabaci Pergande (Thysanoptera:
Thripidae), Western flower thrips Frankiliniella occidentalis Pergande
(Thysanoptera: Thripidae) (Gacheri, 2016; Monsanto, 2017; Nagamandla et al.,
2017).
2.4.1 Damage caused by arthropod pests of tomato
Tomato is infested with diverse range of arthropod pests which results to low fruit yield and quality (Engindeniz and Ozturk, 2013). Arthropod pests account for about 34% of the biotic factors impeding tomato production in
Kenya (Ochilo et al., 2018). Thrips tabaci, F. occidentalis, common blossom
13 thrips Frankiliniella schultzei Trybom (Thysanoptera: Thripidae) and African thrips Ceratothripoides brunneus Bagnall (Thysanoptera: Thripidae), feed beneath the surface of the tomato leaves by piercing and sucking up the sap that exudes from the leaves. Thrips are also destructive to buds, flowers and fruits. The damaged leaves appear silvery with small black spots. Heavily infested buds and flowers may fall off and the fruit may be deformed leading to a reduction in quality. Thrips are also vectors of viral diseases including tomato spotted wilt virus (TSWV) and the Tomato Chlorotic Spot Virus (TCSV) which can lead to 100% yield loss in the field (Ssemwogerere et al., 2013;
Macharia et al., 2015; Szostek et al., 2017).
Whitefly Bemisia tabaci, is a key pest of tomatoes which attacks the crop at all stages of its growth (Sudeepa and Manoj, 2017). This pest sucks sap from the plant leaves thus weakening the plants and results to yellowing.
Whitefly nymphs secrete honeydew a clear sugary liquid which lead to development of black sooty mould. The coating of the sooty mould decreases the photosynthetic area of the plants leading to reduced plant growth. They also cause indirect damage to tomatoes as key vectors of viral diseases such as
Tomato Yellow Leaf Curl Virus (TYLCV), a major disease in Kenya (Marabi et al., 2017).
The tomato leaf miner moth Tuta absoluta is a key pest of tomato
(Goda et al., 2015). The larva (caterpillar) is the most damaging stage which attacks tomatoes from the time of emergence to harvesting (Giorgini et al.,
2019). It mines between the leaf layers producing large galleries. It eventually tunnels into the stems causing breakage. They can burrow into the fruits
14 leaving tiny holes and black frass which lower the quality of fruits. Damaged fruits are prone to entry of fungal diseases, leading to rotting of the fruits before or after harvest. It can cause up to 100% yield losses in an infested field
(Zekeya et al., 2017).
The leaf miner fly Liriomyza spp., is equally a very destructive pest of tomatoes (Stuart et al., 2016). The immature stages (maggots) especially the
2nd and 3rd instar larvae are the most destructive. They feed by mining between the leaf tissues resulting to an irregular track in the form of mines. This results to reduced photosynthetic area affecting development of flowers and fruits.
Heavy infestation may lead to drop off of the leaves, death of the seedlings and exposure of fruits to sunburn thus reducing their quality. During feeding and egg laying, the leaf miners create small punctures on the side of tomato leaves which may act as entry points for harmful micro-organisms such as Alternaria alternata Keissl that causes leaf spot Cercospora capsici Heald on tomato
(Shailendra, 2018).
The African bollworm Helicoverpa armigera is among the most damaging arthropod pest of tomato. The immature stage (caterpillar) feeds on the young and developed fruits of tomato boring into the fruit leading to severe losses (Konje et al., 2019). The damaged fruits eventually decay and rot due to secondary infections caused by other pathogens for example fungi and bacteria.
Through boring the fruits, they can cause up to 70% yield loss (Sumitra et al.,
2012; Kumar, 2013).
Spider mites Tetranychus spp. damage tomatoes by sucking up plant sap using their stylet-like mouth parts. They are usually prevalent in dry areas
15 and are found on the underside of the leaves near the veins (Omukoko et al.,
2017). Infested tomato leaves and fruits show a white to yellow speckling.
Heavy spider mite infestation causes defoliation while attacked plants yield very small fruits with reduced level of vitamin C. Increased infestation of spider mites causes webbing on plants which can result to death of plants.
Tobacco spider mite Tetranychus evansi Baker (Acari: Tetranychidae) is more destructive on tomato and can cause up to 90% yield loss (Jayasinghe and
Mallik, 2013; Ghais et al., 2013).
The root-knot nematodes such as Meloidogyne javanica Treub
(Tylenchida: Heteroderidae) and Meloidogyne incognita Kofoid (Tylenchida:
Heteroderidae) causes significant damage to tomatoes (Wanjohi et al., 2018).
They are most prevalent in tomatoes grown in irrigated sandy soils. The nematode juveniles penetrate the root tips of plants and initiate the development of root knots or galls on the roots which become distorted, swollen and eventually rot (Derrico et al., 2016). Heavy infestations results to stunted growth and wilting of tomatoes (Njoroge, 2014). Tomatoes may even die during hot weather conditions. Root-Knot nematodes can cause up to 60% yield loss in tomatoes (Infonet-biovision, 2019).
2.4.2 Management of arthropod pests of tomato
Several methods are employed in the management of the arthropod pests of tomatoes including cultural, mechanical, physical, biological and chemical measures (Boote et al., 2017; Wakil et al., 2018). The cultural measures used in management of pests of tomato include crop rotation, trap cropping, cultivar
16 selection, plant density, site selection and weed control (Afreen et al., 2017).
Ploughing and harrowing exposes pupae of F. occidentalis and H. armigera which may then be killed by predators such as birds or through desiccation by the sun. Crop rotation with non solanaceous crops such as maize Zea mays L.,
(Graminae) and kales Brassica oleracea var. acephala L., (Brassicaceae) is useful in management of arthropod pests of tomato over successive seasons by breaking the life cycle particularly T. absoluta, A. gossypii, F. occidentalis and
H. armigera (Cherif et al., 2013; Afreen et al., 2017).
Intercropping tomatoes with capsicum Capsicum annum L.,
(Solanaceae) has been found to reduce B. tabaci infestation compared to tomatoes alone or with eggplant Solanum melongena L., (Solanaceae). Also, tomatoes intercropped with garlic Allium sativum L., (Amaryllidaceae) have proved to reduce F. occidentalis infestation on tomatoes (Mugao, 2015).
Helicoverpa armigera can be managed through intercropping of tomato and
African tall variety of marigold Tagetes erecta L., (Asteraceae). (Degri and
Samaila, 2014). Coriander Coriandrum sativum L., (Apiaceae) and fenugreek
Trigonella foenum-graecum L., (Fabaceae) are non-host of B. tabaci and can be planted at the border rows to serve as windbreaks, and are favorable for natural enemies as well as repelling B. tabaci (Sharma et al., 2018). Weeding is essential in reducing the availability of alternate hosts for B. tabaci and T. absoluta such as datura Datura stramonium L., (Solanaceae), volunteer potato
Solanum tuberosum L., (Solanaceae) and eggplant Solanum melongena L.
(Solanaceae) (Infonet-biovisison, 2019).
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Farm hygiene through removal and burning of infested tomato plants during the early stages of infestation has been successful in the control of spider mites (Infonet-biovision, 2019). Appropriate selection of propagation materials from healthy and certified sources is effective in avoiding the introduction of the spider mites in pest free fields (Azandeme-Hounmalon et al., 2014). Adoption of higher plant density helps in reducing aphid populations on tomato. Ultra-violet reflective mulch may be used to manage F. occidentalis by interfering with their host-finding behavior (Demirozer et al.,
2014).
Physical and mechanical pest control measures employed in the management of arthropod pests include use of barriers and traps, handpicking and water spray to knock off pests from infested plants (Akrami and Yousefi,
2015). The coloured blue and yellow sticky traps have been utilized for monitoring and management of F. occidentalis and B. tabaci in the field, respectively (Larki et al., 2012). Covering tomato seedlings in the nurseries with nylon nets has been proved to be effective in reducing B. tabaci infestation. Aluminium-surfaced reflective mulch considerably decreases infestation of F. occidentalis on tomato (Lienneke et al., 2017). Irrigation by flooding tomato fields has been found to reduce the infestation of F. occidentalis through suffocating and killing of large proportion of pupae in the soil. Handpicking and destroying eggs and caterpillars of H. armigera is important in reducing their infestations in especially small plots (Infonet- biovision, 2019).
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Biological control measures have been employed in integrated management of tomato pests (Nyasani et al., 2013). Commercial plant derivatives from neem Azadirachta indica A., (Meliaceae) are used in management of F. occidentalis, A. gossypii, H. armigera, Tetranychus spp. and
B. tabaci (Ramathani et al., 2018). Predators, parasitoids and entomopathogens
(fungi, bacteria and viruses) are also being used as part of integrated pest management strategies (Sabbour, 2014). Trichogramma mwanzai Schulten and
Feijen (Hymenoptera: Trichogrammatidae), an egg parasitoid has successfully been utilized in Kenya as biological control against H. armigera infesting tomatoes (Kalyebi et al., 2015). The predator Conwentzia africana Enderlein
(Neuroptera: Coniopterygoidea) and parasitoid Encarsia formosa Gahan
(Hymenoptera: Aphelinidae), are used in management of B. tabaci (Estefania et al., 2019). The parasitic wasp, Aphidius ervi Haliday (Hymenoptera:
Braconidae), has also been employed against the aphid Macrosiphum euphorbiae Thomas (Hemiptera: Aphididae) on tomato crop. Phytoseiulus persimilis Evans (Mesostigmata: Phytoseiidae) is widely used for management of the two-spotted spider mite Tetranychus urticae Koch (Acari:
Tetranychidae) (Bacci et al., 2019).
Commercial formulations of antagonistic fungi such as Beauveria bassiana Vuill, Verticillium lecanii Zimmermann, Paecilomyces fumosoroseus
Wize and Metarhizium anisopliae Metchnikoff are employed in biological control of B. tabaci, F. occidentalis and Myzus persicae (Surendra, 2017).
Bacterial-based product Bacillus thuringiensis Berliner especially Bt.
19 subspecies kurstaki and Bt. aizawai are available in Kenya for management of
H. armigera on tomato (Samota et al., 2017).
Chemical measures involve application of pesticides to manage the population of arthropod pests infesting the crop. The active compounds in the chemical kill arthropod pests, disrupt mating or inhibit feeding (Nyasani et al.,
2015). Common pesticides used against arthropod pests in tomato production systems in Kenya include imidacloprid, thiamethoxam, alpha-cypermethrin, abamectin, and beta-cyfluthrin, flubendiamide, lamda-cyhalothrin, chloropyrifos, deltamethrin, acephate, acetamiprid, abamectin and malathion
(Ochilo et al., 2018; Bacci et al., 2019).
2.5 Diseases affecting tomato production
Bacterial wilt Ralstonia solanacearum Smith is the most serious disease of tomato in the tropics. The disease is characterized by rapid wilting and death of whole plants without yellowing or spotting of the leaves. The infestation of root knot-nematodes in tomato fields increases the severity of the disease
(Infonet-biovision, 2019). Bacterial wilt can cause up to 90% yield loss
(Mallikarjun et al., 2008). In the absence of the host plants, the pathogen can survive in the soil for an extended period of time (up to 40 years) (Fajinmi and
Fajinmi, 2010; Kanyua, 2018). Bacterial wilt can be managed through long- term crop rotation, removing and burning of all infected plants, field sanitation, bio-fumigation, planting of certified seeds and use of resistant varieties
(Mwangi et al., 2015).
20
Late blight Phytophthora infestans Mont. disease is recognized by the presence of irregular, grayish-black spots that are water soaked in appearance on the leaves. The spots soon expand and turn brown leading to withering of the affected leaves which may collapse but remain attached on the stem
(Alexandrov, 2011). The disease can lead to increased defoliation thus reducing the leaf area for photosynthesis, death of plants and fruits. The disease is spread by wind or droplets of water in plant debris and alternative hosts such as weeds of the nightshade family to vulnerable hosts (Goufo et al., 2008). The development of the pathogen is enhanced by cool moist weather, high temperatures (15-21oC) and relative humidity of 100%. The disease can be managed through integrated strategies such as use of disease-free seedlings, crop rotation, maintaining crop and field hygiene and use of protective chemicals (Infonet-biovision, 2019).
Fusarium wilt Fusarium oxysporum f. sp. lycopersici Schlecht is a soil borne pathogen that infects the plant via the roots to the vascular tissues which lead to famishment of the branches (Manikandan and Raguchander, 2014;
Akrami and Yousefi, 2015). It is characterized by yellowing of the lower leaves of the plant. The pathogen interferes with the roots of the plant thus limiting the translocation of water and nutrients which results to wilting and death of plants (Infonet-biovision, 2019). The warm temperatures range of 25-
32oC, dry weather conditions, acidic soils pH (5.0-5.6), excessive application of nitrogen fertilizer and infestation by root-knot nematodes promotes the development of the disease (Kanyua, 2018). Fusarium wilt can be managed through the use of resistant varieties, crop rotation, avoiding excessive nitrogen
21 fertilization and control of root-knot nematodes (Mwangi et al., 2017; Melese and Samul, 2018).
Early blight Alternaria solani Sorauer is a fungal pathogen that affects tomato fruit and at the end of stems causing extensive sunken-like areas with concentric rings that appears black (Junior et al., 2011). The leaves of affected plants may fall off leading to reduction in the yield of fruits (Ashour, 2009).
The disease can be controlled by practicing crop rotation, use of drip irrigation, appropriate soil fertility and use of recommended copper based preventive fungicides such as copper hydroxide especially during fruit setting stage
(Nashwa and Abo-Elyousr, 2012).
2.6 Use of entomopathogenic fungi in crop protection
Entomopathogenic fungi are essential microbial control strategies of diverse arthropod pests of agricultural crops (Sharma et al., 2012; Eliska,
2015). Their use as alternatives to synthetic pesticides or in combination with pesticides could be effective in the management of resistance to pesticides.
Entomopathogenic fungi such as Metarhizium anisopliae Metchnikoff,
Paecilomyces fumosoroseus Wize and Verticillium lecanii Zimmermann have multiple modes of action as they do not have to be ingested to cause infection.
An entomopathogenic fungus infects arthropod pests by breaching through the pest integument using the hyphae responsible for production of numerous enzymes and toxins (Ortiz-Urquiza and Keyhani, 2013). This is followed by penetration of the conidia into the cuticle, enhanced by enzymatic degradation and pressure of the germ tube (Khan et al., 2012).
22
The development of infection by an entomopathogenic fungus is dependent on relative humidity, behavior of the host, microbial antagonists, sensitivity to solar radiation, physiological condition, temperature and inoculum thresholds (Starnes et al., 2013; Borisade and Magan, 2015; Bayissa et al., 2017; Castilho et al., 2018).
2.7 Mechanism of suppression by entomopathogenic fungi against
arthropod pests
Entomopathogenic fungi are regarded as key natural regulators for a wide range of arthropod pests of economic importance in agriculture, which significantly kill host insect populations by epizootics. Most fungal antagonists of arthropod pests are host-specific and harmless to non-target beneficial organisms in the environment (Eliska, 2015).
The stages involved in the pathogenicity of the fungal pathogens are adhesion, germination, differentiation and penetration (Sandhu et al., 2012;
Castilho et al., 2018). Adhesion of the fungal pathogen to an insect cuticle is the primary element that influences its virulence. This is followed by secretion of the enzymes (lipases, proteases and chitinases) which hydrolyzes the epidermis of the insect integument (Fedai and Ozgur, 2015).
The germination of the spore on the insect cuticle is influenced by fatty acids, ions, water, nutrients present on the insect’s integument and the physiological condition of the individual arthropod pest (Ortiz-Uquiza and
Keyhani, 2013). Complete germination of the spore is enhanced by combination of useful nutrients and tolerance to harmful substances available
23 on the surface of the host insect pest. Upon germination, appresoria develop at the terminal of short germ tubes or at side branches (Pucheta et al., 2016). The entry of the insect integument is via integration of mechanical and enzymatic forces achieved by the germ tube itself or by the formation of an appressorium that attaches to the cuticle and creates a thin penetration peg (Mondal et al.,
2016).
2.8 Methods of application of entomopathogenic fungi in in-vitro bioassays
Bioassay methods commonly employed in in vitro pathogenicity tests include topical application, injection, ingestion and dipping methods
(Paramasivam and Selvi, 2017). Topical technique involves allowing the insect pests under test to crawl on the sporulated cultures of the fungal isolates on
Potato Dextrose Agar (PDA) slants for some time and the amount of conidia attached to the cuticle of the insect pests can be anticipated. This method usually depends on the size of the insect pest, the number of insects to be inoculated, formulation used and the desired level of precision to be achieved
(Durmusoglu et al., 2015).
The injection technique involves inoculation of insect pests by injecting an initial aqueous suspension of inocula directly into the insect integument
(thorax) using a syringe fitted with a hypodermic needle. The quantity of the fungal suspension is determined by the size of the insect pest. In the study of immunological responses of insects this method is the most preferred
(Paramasivam and Selvi, 2017).
24
The ingestion method involves introducing the inoculum to insect pests through a secondary substrate. The insects pick up the inoculum by contact with the substrate as they feed or move across the substrate (Silva et al., 2017).
Dipping technique is used incase topical or injection methods are unfeasible. In this approach, a pair of forceps is used to pick up the insects and immerse into an aqueous solution of an entomopathogenic fungus for about 5 seconds (Enver et al., 2015). Dipping method can also be achieved by dipping leaves in aqueous solution of inoculum of different concentrations for certain period of time. The leaves are then drained off excess solutions and air dried before releasing a known number of insect pests to feed on the treated leaves and the mortality counts are recorded after a certain period of time (Civolani et al.,
2014).
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CHAPTER THREE: MATERIALS AND METHODS
3.1 Determination of occurrence of major arthropod pests of S.
lycopersicum in Bungoma County, Kenya
3.1.1 Description of study areas
A survey was conducted in June, 2017 in Bungoma County situated in
Western Kenya. Farming is the main economic activity in the County with farmers engaged in cultivation of crops and livestock keeping. Crops grown include maize, beans, finger millet, potatoes and vegetables such as tomatoes, kales and cabbages. Bungoma is among the key tomato producing Counties in
Kenya dominated by small-scale farmers (HCDA, 2018; NAFIS, 2018).
The survey was conducted in three sub-counties namely Mt. Elgon,
Sirisia and Bumula (Figure 3.1). These sub-counties were selected based on their prominence in producing significant tomato in the County and represented different production agro-ecological zones. Mt. Elgon sub-county lies between
1°10´12´´N and 34°19´48´´E with altitude ranging from 1,547 to 1,856 m above sea level (ASL) on lower highland agro ecological zone 1 (LH1).
Bumula sub-County is found on lower midland zone 4 (LM4) between
0°37´12´´N and 34°27´36´´E with altitude ranging from 1,301-1,467 m ASL.
Sirisia sub-County is found in (LM2) between 0°45´0´´N and 34°30´36´´E with an altitude ranging from 1,354 to 1,508m ASL.
The sub-counties have varying soil types, with inherently fertile deep rich Andosols, Acrisols and Nitisols found in Sirisia, Bumula and Mt. Elgon, respectively (Jaetzold et al., 2012). The County experiences average annual temperatures between 15o to 23oC. The region receives bimodal rainfall
26 ranging from 950 mm to 1,500 mm per annum, with the long rainy season between March to July and short rainy season between August and November
(Bungoma CIDP, 2017).
Figure 3.1: Map of Bungoma County showing the surveyed Sub-Counties
(Mt. Elgon, Sirisia and Bumula).
(Source: Google maps). Accessed on 15/01/2019
3.1.2 Determination of tomato production practices
A sample of ninety respondents from accessible households were selected using a combination of simple random sampling and snow ball sampling technique based on Nassiuma (2000) formula: n =Sample size, N=
Size of the target population which was 900 tomato farmers, C= Coefficient of
27 variation (0.5) and e= Margin of error (0.05). Substituting the values in the above equation, estimated sample size was: n= 900 (0.5)2/0.52+ (900-1) 0.052 n=90 respondents. Sub-county Agricultural extension officers and village elders helped to identify the survey areas and farmers who had grown tomatoes during the study.
A structured questionnaire (Appendix I) was administered to each respondent farmer through face to face interviews. A total of 41 farmers from
Sirisia, 29 from Bumula and 20 from Mt. Elgon sub-County who were active in tomato farming were identified for data collection. A Global Positioning
System (GPS) was used to determine the coordinates of the farmers’ fields.
The information gathered included social economic characteristics such as farm size, gender, age, level of education, period the farmers has been active in farming, knowledge on the major pests infesting tomatoes and practices used in management of the pests and diseases on tomato. Photo-cards of tomato pests and disease symptoms (Appendix II).were used to assist the farmers in identification of the arthropod pests.
3.1.3 Assessment of occurrence of major arthropod pests of tomato
Pest incidences and damage on tomatoes from the farmers’ fields was determined visually as described by NICRA (2012). Twenty tomato plants per vegetative, flowering and fruiting stage were randomly selected from each field and physically checked for presence of pests using features such as presence of eggs, honeydew, feacal material, exuvium, cocoon, webbing on leaves, windowing and tunnels on leaves. Immature and adult stages of the pests detected in fields were collected by carefully detaching the infested plant parts, 28 placed in labeled plastic vials stored in a cool box and taken to Kenyatta
University laboratory for pupation and adult emergence. The pupae were picked using forceps and placed individually in 100 ml plastic vials for adult emergence. Morphological features were used to identify the adult arthropod
pests as described by Moritz et al. (2013).
3.2 Evaluation of insecticidal activity of antagonistic fungi in biological
control of Western flower thrips in vitro
3.2.1 Sources of fungal antagonists
A total of ninety soil samples were collected from the rhizosphere of tomato plants. These comprised of 41 surveyed fields in Sirisia, 29 in Bumula and 21 in Mt. Elgon in Bungoma County. The soil was scooped using a soil auger at a depth of 10 cm after removing 2 cm of the top soil. For every field, five soil samples were collected and mixed to make a composite sample of
500g which was packed in sterilized polythene bags, sealed, labeled accordingly and placed in a cool box as described by NouriAiin et al. (2014).
Insect cadavers were also collected from tomato fields and placed in 100 ml plastic vials. The samples were taken to Kenyatta University Agricultural laboratory for storage, air drying and isolation of the microbial antagonists.
3.2.2 Preparation of culture media
The culture media was prepared by dissolving 39 g of Potato Dextrose
Agar (PDA) in 1,000 ml of distilled water and autoclaved (UTKBS-V Series) for 15 min at 121oC. The autoclaved PDA medium was allowed to cool to 45oC in a water bath and amended with antibiotics (tetracycline) at a rate of 100 mg
29
L-1 under sterile conditions in a laminar flow cabinet using a micropipette as described by Rioux et al. (2014). The antibiotics (tetracycline) were used to inhibit bacterial growth in the mixture.
3.2.3 Isolation of antagonistic micro-organisms
Micro-organisms from the materials collected from the field were isolated by pour plate technique (Shobha and Kumudini, 2012; Belete et al.,
2015). Suspension of soil samples was prepared by addition of 1g soil into 9 ml of distilled water and mixed rigorously by agitation in a magnetic shaker
(Heidolph Unimax 1010) set at 150 revolutions per minute. Thereafter, serial dilutions of 10-1, 10-2 and 10-3 of the prepared soil suspensions were made
(Belete et al., 2015).
One milliliter aliquot of serially diluted suspension from each dilution was pipetted into sterile 9 cm diameter disposable petri dish containing PDA amended with antibiotics. The petri dishes were sealed with parafilm and placed in an incubator (BJPX-H230JI) for seven days under room temperature at (23 ± 2 ºC) for fungal growth as described by Abu and El-Hindi (2017).
3.2.4 Purification, identification and storage of fungal antagonists
Seven days after incubation, the fully sporulated fungal cultures were sub-cultured on new PDA medium to make pure cultures. A segment of mycelium from the sporulating colonies in each pure culture was transferred onto glass slides and stained with a drop of lactophenol cotton blue solution.
Thereafter, the slide was examined under a compound microscope (XSZ-107T) at a magnification x40 for characteristics of their vegetative and reproductive
30 structures such as hyphae colour, size, shape of conidia and conidiophores. The fungal isolates were identified using the key described by Watanabe (2010) and maintained on PDA slants stored at 40 C in a refrigerator until required for bioassays.
3.2.5 Collection and maintenance of Western flower thrips Frankliniella
occidentalis
Initial colonies of F. occidentalis were collected from infested tomatoes in Sirisia, Bumula and Mt. Elgon in Bungoma County during field surveys conducted in June 2017. The specimens of F. occidentalis were processed at
Kenyatta University (KU) Agricultural Research Laboratory, to confirm their identity using various identification keys (Moritz et al., 2013). The thrips were reared in 3L modified clear plastic buckets. A 15cm diameter hole was cut on the lid and the sides of the cages covered with thrips-proof organdy cloth to allow ventilation. The insect colonies were maintained in the laboratory at 23 ±
2 °C, 60 ± 10% RH.
The adult F. occidentalis were aspirated from the collection vials and transferred into 3L clear plastic buckets and fed on French bean pods
Phaseolus vulgaris L. var Samantha for three days to allow for egg laying.
After three days, the French beans were transferred to new clear plastic buckets lined with paper towel at the bottom for development of the nymphs, pupa and adult emergence. The newly emerged adults were consecutively transferred to new rearing plastic buckets provided with French bean pods to allow the development of the next generation for use in the in vitro experiment.
31
3.2.6 Preparation of conidial suspensions for in vitro bioassay
Conidia of potential entomopathogenic fungi were harvested by scraping off the sporulating colonies on PDA medium with a sterilized glass rod and suspended in distilled water containing 0.05% Tween-20 (v/v aqueous solution), a surfactant and filtered through a muslin cloth as described by
Borisade and Magan (2015). The conidial suspension was agitated using a magnetic shaker (Heidolph Unimax 1010) set at 150 revolutions per minute to get a homogeneous suspension. Spores were counted using an improved
Neubauer haemacytometer and suspensions diluted with distilled water to make the final concentration of approximately 1.0x107 conidia ml-1 for use in the pathogenicity test (Masoud and Bahar, 2012).
3.2.7 Screening of fungal isolates against Frankliniella occidentalis in vitro
The effect of the antagonistic fungi on the mortality of nymphs and adults of F. occidentalis was determined by treating them with concentrations of 1x107 conidia ml-1 (Gao et al., 2012). A control comprised of sterile water with Tween-20 at 0.05% (v/v). Twenty nymphs and adult F. occidentalis were collected from the rearing cages and dipped in the fungal suspension for 5 seconds to allow spread of the fungal suspensions on the thrips cuticle. The treatments were replicated four times and arranged in a completely randomized design (CRD). Twenty thrips were allowed to air dry on the sterile filter paper and transferred to 9cm diameter petri dishes using sterile camel hair brush. The thrips were provided with 2 cm wide discs of French bean as diet. The petri
32 dishes were then sealed with parafilm and incubated in the laboratory at 23 ± 2
ºC.
Mortality of F. occidentalis was recorded daily for 10 days (Youssef,
2015). Dead F. occidentalis were mounted on a dissecting microscope (NTB-
3A) and observed at x10 magnification for presence of fungal mycelia which was used as a symptom of mycosis. Mortality was computed as percentage based on Marek (2010) formula:
Number of dead insects Percent mortality = Total number of exposed insects x 100
3.3 Determination of the effectiveness of fungal antagonists in
management of Frankliniella occidentalis under field conditions
3.3.1 Description of experimental site
On-farm trials were carried out during the long rainy season (March -
July, 2018) and short rainy season (August -November, 2018) at Bukonoi and
Cheptais in Bungoma County, Kenya. Bukonoi lies between 0°48´36´´N and
34°28´12´´E at an elevation of 1,635 m ASL with sandy clay soils while
Cheptais is located between 0°48´0´´N and 34°27´36´´E at an altitude of 1,593 m ASL and comprised of sandy clay loam soils. Both Bukonoi and Cheptais receives bimodal rainfall ranging from 950 to 1,500 mm per annum with the long rains between March to July and short rains between August to November
(Jaetzold et al., 2012). The average annual temperatures range from 15o to
23oC (NAFIS, 2018; Bungoma CIDP 2013-2018).
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3.3.2 Mass production of antagonistic fungi and preparation of inoculum
Five active candidate fungal antagonists Trichoderma virens 1,
Trichoderma virens 2, Trichoderma afroharzianum, Fusarium solani and
Fusarium oxysporum were selected based on their virulence against thrips in in vitro experiments (Table 4.8). These were propagated on sorghum grains
(Serena variety) as a substrate for mass multiplication since it is locally available and has shown good performance as a substrate (Singh et al., 2014;
Kumar et al., 2014). Sorghum grains were purchased from the cereal shops in
Nairobi and pre-soaked for 24 hours in water. The water was decanted and two hundred grams of sorghum grains was weighed and placed in 500 ml glass beakers. Each beaker containing the sorghum grains was wrapped with aluminium foil as it is resistant to heat. The contents in the beakers were then autoclaved at 121ºC for 20 minutes and left for 2 hours to cool at room temperature. The cooled substrate was aseptically transferred separately into clear transparent polythene bags measuring 9 cm x 15 cm. Five 10 mm discs of each of the fungal isolates were cut separately with sterilized 10 mm cork borer and inoculated in the sorghum substrate using a sterile wire loop under aseptic conditions in the laminar flow cabinet (BBS-H1100). The substrates in the polythene bags were incubated at 23 ± 2 0C for 14 days.
Throughout the incubation period, the substances in the polythene bags were manually shaken vigorously after every two days to prevent clumping and improve aeration as described by Sivakalai and Ramanathan (2015). After 14 days the fungal antagonists were transferred into sterile plastic trays (25 cm x
20 cm) wrapped with a serviette on top and tied with a rubber band. The fungal
34 antagonists were allowed to air dry for 10 days at room temperature and blended using an electric blender. The fungal antagonists were mixed with talcum powder in the ratio of 1:2. The talcum powder was used as a carrier of the fungal antagonists.
One gram sample of each fungal antagonist was weighed and suspended in 9 ml distilled water in separate universal bottles. The suspension was shaken in a mechanical shaker (Unimax 1010) for 10 minutes and filtration was done using two layered muslin cloth. The concentration of fungal antagonists was standardized through serial dilution to 1×108 conidia g-1. The blended conidia were packed in sealed polythene bags (30 cm x 20 cm), labeled and stored in the cool box (containing ice blocks) for use in the field.
3.3.3 Field experiment layout, design and data collection
Field experiments were set up in farmers’ fields at Bukonoi and
Cheptais. The seeds of tomato variety Rio-Grande; a common variety grown in the experimental sites were established. Three nursery beds each measuring 2 m by 1 m raised 0.15 m above the ground were prepared using a hoe. Shallow furrows about 0.01 m and 0.15-0.20 m apart across the beds were made and di- ammonium phosphate (18% N, 46% P2O5) fertilizer was mixed with the soil prior to sowing the seeds. The nursery beds were covered lightly with soil and dried grass was put as mulch. After sprouting, the mulch was removed and a shade made over the beds at 1m. The seedlings were watered three times a week. One week before transplanting, watering was reduced and the shade removed to harden the seedlings.
35
The experimental field was manually prepared using a hoe. The field was divided into 32 plots, each measuring 4m by 3m with 1m alleys between the plots and 1m alleys between the blocks. The field trial was arranged in a randomized complete block design (RCBD) replicated four times. The transplanting holes were dug using a hoe. Di-ammonium phosphate (18% N,
46% P2O5) was applied at the rate of 10 grams in each hole and rigorously mixed with the soil before transplanting.
Twenty eight days old healthy tomato seedlings were transplanted in the evening to reduce transplant shock. They were transplanted at a spacing of
0.6 m x 0.3 m with each experimental plot having about 66 tomatoes (Infonet- biovision, 2019). Gapping of dead seedlings was done one week after transplanting (WAT). Weeding was done at 3, 6 and 9 WAT. Calcium ammonium nitrate (CAN) was applied at a rate of 10 g per plant at 4 WAT.
Antagonistic fungi described in section 3.3.2 above were compared against commercially formulated bio-pesticides (Bio-power, Commercial
Beauveria bassiana), commonly used synthetic pesticide Confidor 70 WG®
(Imidacloprid) and control (sprayed with water). Treatments were applied once at 7 days interval from 3 WAT to harvesting. All treatments were applied as foliar sprays using CP 15 s knapsack sprayer (Cooper Pegler and Co. Ltd,
Sussex, England). For spray applications, 1 g conidia of fungal isolates were weighed in the laboratory and the spore concentrations were determined by counting the spores using a Neubauer haemocytometer under a compound microscope (XSZ-107T) at x40. The final working concentration was obtained using the formula by (Goettel and Inglis, 1997). N/V x D where N= number of
36 conidia, V= volume of the chamber (constant of 2.5 x 105), D= dilution factor.
From these spore concentrations; it was possible to calculate the amount of fungal conidia spores to be weighed to give a spore concentration of 1x108 spores L-1 of water to be used in the field.
The weighed fungal conidia for the spore concentration of 1x108 were suspended in water containing 0.05% Tween-80 solution as a wetting agent.
Spraying was done in the evenings between 16:00 h and 18:30h to lessen the adverse effects of ultraviolet radiation (Mustafa and Kaur, 2009). Bio-power was applied at the rate of 100 g in 20 L of water while Confidor® WG 70
(imidacloprid 700g Kg-1) at the recommended rate of 5 g in 20 litres of water.
The control plots were treated with water only.
The assessment of flower thrips population was conducted at early hours of the day between 7.00-10.00 am as described by Shafie and
Abdelraheem (2012). This was done five times from 6 to 10 WAT. Twenty well developed flowers from 20 randomly tagged tomatoes in the inner rows per plot were cut and placed in high density plastic poly pots (35 ml) containing 70% ethanol. The flowers were placed in Petri dishes, dissected and washed with water to ensure that none of the thrips was lost with the debris.
The number of thrips were counted using the tally counter under the dissecting microscope (NTB-3A) at X10 magnification and recorded.
Harvesting of tomatoes was initiated 12 WAT. Ripe tomatoes from each plot were harvested and placed in labeled khaki bags. The weight of all tomatoes in Kilograms per plot was determined using a digital hand held
37 electronic scale. Tomatoes were graded and categorized into marketable and unmarketable as described by FAO (2018).
3.4 Data analysis
Survey data on social economic characteristics of respondents namely gender, age, level of education, farm size, major pests and diseases affecting tomato and their management practices were reviewed, cleaned, organized and coded in Microsoft Excel spreadsheets and analyzed using Statistical
Programmes for Social Sciences (IBM SPSS Statistics 18) to obtain frequencies and percentages of the variables studied. In vitro data on percentage mortality of adult and nymphs of F. occidentalis, field data on F. occidentalis population, total marketable and unmarketable yields were subjected to one way analysis of variance (ANOVA) using Statistical Analysis
Software (SAS) version 9.4 (SAS Institute, 2013). Mean separation was accomplished according to Student Newman-Keuls (SNK) test at P≤0.05 only where significant differences was realized.
38
CHAPTER FOUR: RESULTS
4.1 Occurrence of major arthropod pests of tomato in Bungoma County
4.1.1 Tomato production characteristics
The survey results revealed that men were more involved in tomato cultivation across the Sub-counties as opposed to women with Mt. Elgon having 89.7 % of growers being male (Table 4.1). Majority of the farmers were between 41-45 years accounting for 37.9% in Mt Elgon, 25% in Bumula and
22% in Sirisia Sub-County. Most of the farmers interviewed had attained up to primary education level across the sub-counties, with 75.6 % in Sirisia, Mt.
Elgon (55.2%) and Bumula (50%). About 2.4% of the respondents in Sirisia had not attained any formal education (Table 4.1).
39
Table 4.1: Gender, age and the education level of tomato growers in
Bungoma County
Percent (%) respondents per Sub-County
Variable Sirisia Bumula Mt. Elgon
Gender Male 85.4 80.0 89.7
Female 14.6 20.0 10.3
Age in years <25 - 5.0 -
26-30 4.9 - 3.4
31-35 22.0 15.0 17.2
36-40 9.8 20.0 34.5
41-45 22.0 25.0 37.9
46-50 14.6 5.0 6.9
51-55 14.6 15.0 -
>55 12.2 15.0 -
Education level None 2.4 - -
Primary 75.6 50.0 55.2
Secondary 19.5 45.0 41.4
Post-secondary 2.4 5.0 3.4
40
The study indicated that total farm sizes in all the Sub-Counties ranged from 0.25 to 2.0 hectares. Majority of the respondents had farm sizes ranging from 0.25 to 1.0 hectares with 80.5% in Sirisia Sub-county, with only 2.4 % of the respondents in Sirisia Sub-county owned above 2 hectares of land (Figure
4.1).
90 Sirisia Bumula
Mt.Elgon 80 70 60 50 40 30 20
Percent (%) respondents Percent 10 0 0.25-1.0 1.1-1.5 1.6-2.0 >2
Farm size (Ha)
Figure 4.1: Farm sizes of tomato farmers in Bungoma County
It was observed that Rio-Grande was the most popular variety grown in open fields in all the sub-counties with 44.8% cultivated in Mt. Elgon, 41.5% in Sirisia and 35.0% in Bumula Sub-county. Carl-J variety which was mainly grown in Bumula and Sirisia accounting for 50% and 24.4%, respectively.
Elgon Kenya variety was predominantly cultivated in Mt. Elgon with 20.7% followed by Sirisia (14.6%) and Bumula (5%). Kilele was the least popular tomato variety grown in Bungoma County with only 2.4% of the respondents in Sirisia. Ana F1 was the only variety grown by farmers under greenhouse conditions with only 5% of the respondents in Bumula sub-county (Figure 4.2).
41
60 Sirisia Bumula Mt Elgon 50 40 30 20 10 Percent respondents (%) Percent 0
Tomato varieties
Figure 4.2: Tomato varieties grown by respondents in Bungoma County
The study revealed that majority of farmers had been active in tomato production for more than five years accounting for 86.2% in Mt. Elgon followed by Bumula (70%) and Sirisia (51.2%) (Table 4.2).
Table 4.2: Farmers’ experience in tomato production in Bungoma County
Percent per Sub-County
Farming experience Sirisia Bumula Mt Elgon
<1 year 0.0 0.0 0.0
2yrs 19.5 5.0 0.0
3yrs 22.0 20.0 6.9
4yrs 7.3 5.0 6.9
>5yrs 51.2 70.0 86.2
42
4.1.2 Occurrence of arthropod pests and diseases of tomato in Bungoma
County
Six arthropod pests including F. occidentals, T. absoluta, B. tabaci, H. armigera , Tetranychus spp., and M. persicae infested tomato crop in Bungoma
County (Plate 4.1).
A B
C D
Plate 4.1: Major pests identified infesting tomatoes in Bungoma County; A: F. occidentalis B: T. absoluta, C: M. persicae, D: B. tabaci. (X10 Mg) (Source: Barasa, 2017) 43
Tuta absoluta was abundant in Sirisia followed by Mt. Elgon and least in Bumula Sub-county accounting for 29.3%, 27.7% and 5%, respectively.
Frankliniella occidentalis was most prevalent in Mt. Elgon sub-county with
58.6% followed by 31.7% in Sirisia and 30% in Bumula. About 35%, 17.1% and 10.3% of B. tabaci were reported in Bumula, Sirisia and Mt. Elgon, respectively. Helicoverpa armigera accounted for 30%, 14.6% and 3.4% in
Bumula, Sirisia and Mt. Elgon, respectively. Tetranychus sp. and M. persicae were only reported in Sirisia accounting for 4.9% and 2.4 %, respectively
(Figure 4.3).
70
60 Sirisia Bumula Mt. Elgon
50
40 occurrence
30
20 Percent (%) Percent 10
0 TA FO BT T HA MP Arthropod pest
Figure 4.3: Arthropod pests of tomato in Bungoma County TA-Tuta absoluta, FO-Frankliniella occidentalis, BT-Bemisia tabaci, T-Tetranychus sp., HA-Helicoverpa armigera, MP-Myzus persicae
It was observed that Ralstonia solanacearum was the major disease limiting tomato production across the three sub-counties accounting for 75% in
Bumula. The highest incidence of P. infestans (24.1%) and Fusarium
44 oxysporum (17.1%) was recorded in Mt. Elgon and Bumula respectively
(Figure 4.4).
Sirisia Bumula Mt. Elgon
80
70
idence 60
inc 50 40 30
Percent (%) Percent 20 10 0 Bacterial wilt Fusarium wilt Early blight
Tomato disease
Figure 4.4: Diseases affecting tomato production in Bungoma County
4.1.3 Management of pests and diseases of tomato in Bungoma County
All farmers used synthetic chemicals in management of pests and diseases. They relied on either single or a combination of chemicals. The pesticides used by farmers included Lambda cyhalothrin, Imidacloprid,
Acephate, Alpha-Cypermethrin and Flubendiamide. Imidacloprid, Lambda cyhalothrin and Alpha-Cypermethrin were the most common pesticides used accounting for 24.4% in Sirisia, 30% in Bumula and 20.7% in Mt. Elgon respectively (Table 4.3). The fungicides used to control diseases included
Metalaxyl-M, Propineb+Cymoxanil, Mancozeb, Propineb and Carbendazim
(Table 4.4). Results of this study found that the majority of farmers (60%) in
45
Bumula combined chemicals followed by 22% in Sirisia and 20.7% in Mt.
Elgon sub-County (Table 4.3).
Table 4.3: Chemicals used by farmers in management of tomato pests in
Bungoma County
% use per sub-County
Chemical active ingredient Target pest/disease SRS BML ME
Lambda-Cyhalothrin Thrips, whiteflies 19.5 30 6.9
Imidacloprid Thrips, whiteflies 24.4 20 -
Acephate Aphids, thrips 2.4 5 -
Alpha-Cypermethrin whiteflies 4.9 5 20.7
Flubendiamide Leaf miner moth 2.4 - -
Other chemicals
Mancozeb, Lambda-cyhalothrin Blight, whiteflies 7.3 - 10.3
Mancozeb, Imidacloprid Blight, thrips 2.4 5 13.8
Lambda-cyhalothrin, Imidacloprid Thrips, whiteflies 17.1 5 3.4
SRS-Sirisia; BML-Bumula; ME-Mt. Elgon
46
Table 4.4: Chemicals used by farmers in the control of diseases on tomato
% use per sub-County
Active ingredient Target disease(s) Sirisia Bumula Mt. Elgon
Metalaxyl-M Blight, Leaf spots 9.8 10 3.4
Propineb+Cymoxanil Blight, Leaf spots 17.1 - -
Mancozeb Blight 4.9 10 17.2
Propineb Blight, Black spots 4.9 3.4
Carbendazim Leaf spot, mildew 2.4 - -
Other chemicals
Metalaxyl-M,
Propineb+Cymoxanil Blight 22 60 3.4
Metalaxyl-M,
Cypermethrin Blight 17.1 5 20.7
Propineb+Cymoxanil,
Cypermethrin Blight 14.7 10 13.8
4.1.4 Chemical application practices on management of tomato pests in
Bungoma County
In Sirisia Sub-County, all respondents used chemicals once on weekly basis. About 10% and 6.9% respondents in Bumula and Mt. Elgon Sub-county respectively applied chemicals twice a week to control arthropod pests and
47 diseases. At least 53.8% of the growers in Sirisia Sub-county indicated that the pesticides were effective in managing the pests while 61% and 58.7% of the respondents in Bumula and Mt. Elgon correspondingly stated that they were ineffective. About 97.6% of the respondents in Sirisia were unaware of safer alternatives to synthetic chemicals such as biological control strategy in integrated pest management (IPM). A minimal 2.4% of respondents in Sirisia sub-county had knowledge on biological control strategy (Table 4.5).
Table 4.5: Chemical application practices on tomato production in
Bungoma County
% respondents per sub-County
Sirisia Bumula Mt Elgon
Spray frequency Weekly 100 90 93.1
Twice a week - 10 6.9
Effectiveness of the chemical Effective 53.8 39 41.3
Not effective 46.2 61 58.7
Use of biological control Yes 2.4 - -
No 97.6 100 100
4.1.5 Farmers’ sources of information on the use of chemicals in
controlling tomato pests and diseases in Bungoma County
Farmers relied on different sources for information on use of chemicals in tomato production. About 41.5% of the respondents in Sirisia Sub-county
48 relied on other farmers while 65% and 62% of respondents in Bumula and Mt
Elgon, respectively relied mainly on Agrovet sellers (Table 4.6)
Table 4.6: Most available sources of agricultural information on tomato
production in Bungoma County
% respondents per sub-County
Source Sirisia Bumula Mt. Elgon
Agricultural extension officer 2.4 - -
Agrovet shop sellers 39 65 62.1
Other farmers 41.5 30 24.1
Mass media 7.3 - -
Own experience 9.8 5 13.8
4.2 Evaluation of insecticidal activity of antagonistic fungi in biological
control of Frankliniella occidentalis in vitro
4.2.1 Entomopathogenic fungi isolated from soil
A total of 40 fungal species were isolated from the soil samples with two species recovered from the insect cadavers. These belonged to different genera, Trichoderma, Verticillium, Fusarium, Penicilium and Plactosporium.
Most of the fungal isolates were from the genus Trichoderma with
Trichoderma harzianum being the predominant species comprising nine isolates from Sirisia, three from Bumula and two from Mt. Elgon. Two fungal
49 species, Plactosporium tabacinum and Penicilium resticulosum were recovered from F. occidentalis and T. absoluta cadaver, respectively (Table 4.7).
Table 4.7: Fungal species tested against F. occidentalis and their origin
Isolation locality
Fungal isolate Source SRS BML ME
Trichoderma harzianum Rifai Soil 8 3 2
Trihoderma afroharzianum Chaverri Soil 1 - -
Trichoderma koningi Oude Soil 3 1 1
Trichoderma aureoviride Pers Soil 1 - 1
Trichoderma koningi Oude. Soil 1 - -
Trichoderma virens 1 Mill Soil 1 - -
Trihoderma virens 2 Mill Soil - 1 -
Fusarium oxysporum Snyder Soil - 1 -
Verticillium balanoides Dowsett Soil 1 - -
Verticillium dahliae Kleb Soil - - 1
Fusarium ventrichosum Link Soil 1 - -
Fusarium solani Mart Soil 1 - -
Penicilium jantinellum Biourge Soil - - 1
Plactosporium tabacinum Beyma Thrip 1 - -
Penicilium resticulosum Birkinshaw T. absoluta - - 1
SRS-Sirisia; BML-Bumula; ME-Mt. Elgon
50
4.2.2 Efficacy of fungal isolates against F. occidentalis in vitro
All tested fungal isolates including T. harzianum, T. virens, T. afroharzianum, F. solani, F. oxysporum, F. ventrihosum, T. koningi, T. pseudokoningi, T. aureoviride, V. dahliae, V. balanoides, P. resticulosum, P. jantenillum and P. tabacinum were pathogenic to the nymphs and adults of F. occidentalis at a concentration of 1x107conidia ml-1. They recorded mortality of between 23 and 62%. Mortality in the control treatment was lower and did not exceed 4% for nymphs and 15% for adults. Among the twenty fungal isolates, T. virens 1, T. virens 2, F. solani, F. oxysporum and T. afroharzianum were more virulent causing mortality of ≥ 50% (Table 4.8; Plate 4.2).
Trichoderma virens 1 (Plate 4.3) caused the highest mortality of 62.2% in adults and 43.8% in nymphs at 1.0 x 107 conidia ml-1, which was significantly different compared to other isolates (F=40.70; df=19, 23;
P<0.0001). There were significant differences among V. dahliae and P. tabacinum, T. koningi 1 and F. ventrichosum in their effect on the adults (F=
40.70; df=19, 23; P<0.0001). The effect between T. koningi 1 and P. resticulosum on the nymphs of F. occidentalis was significant (F=24.40; df=19, 23; P<0.0001). Trichoderma sp. and T. koningi 2 were significantly different on mortality of adult F. occidentalis (F= 40.70; df=19, 23; P<0.0001)
(Table 4.8).
51
Table 4.8: Efficacy of fungal isolates against F. occidentalis in vitro
Mean mortality (% ± S.E)
Isolation locality Fungal isolate Adults Nymphs Sirisia Trichoderma harzianum 37.8±3.9de 33.3±3.1bcd Sirisia Trichoderma harzianum 37.8±3.9de 33.3±3.1bcd Sirisia Trichoderma harzianum 37.8±3.9de 33.3±3.1bcd Sirisia Trichoderma pseudokoningi 1 33.7±4.2ef 27.5±3.7de Sirisia Trichoderma pseudokoningi 2 31.7±3.4f 28.7±3.2cde Sirisia Trichoderma aureoviride 43.2 ±4.7d 33.2±2.3bcd Sirisia Verticillium balanoides 42.7±4.6d 34.7±3.6bcd Sirisia Trichoderma virens 1 62.2±5.4a 43.8±4.2a Sirisia Penicilium resticulosum 28.7±3.0fg 24.0±3.1e Sirisia Fusarium ventrichosum 30.8±5.0f 28.3±3.3cde Sirisia Fusarium solani 56.0±6.1bc 38.8±5.6ab Mt. Elgon Trichoderma koningi 1 40.0± 4.2d 39.2±4.8ab Mt. Elgon Trichoderma pseudokonigi 3 37.5±5.0de 30.8±3.6bcde Mt. Elgon Trichoderma spp. 25.3 ±3.1g 27.2±3.9de Mt. Elgon Verticillium dahliae 40.0±4.6d 37.3±3.9abc Mt. Elgon Penicilium jantinellum 38.7±4.5de 30.3±3.5bcde Mt. Elgon Plactosporium tabacinum 31.5± 3.2f 23.2±3.4e Bumula Trichoderma koningi 2 24.5±3.7g 27.7±3.4de Bumula Trichoderma virens 2. 57.3±5.4ab 39.3±3.9ab Bumula Fusarium oxysporum 54.5±6.0bc 38.7±4.8ab Control 15.83±2.9h 4.0±1.4f F=40.70 F=24.40 df=19, 23 df=19, 23 P<0.0001 P<0.0001 Means followed by the same letter (s) in each column are not significantly different according to Student Newman-Keuls (SNK) test at P≤0.05.
52
a b
c d
Plate 4.2: Isolated fungal antagonists in vitro bioassay; a): Trichoderma. virens 1, b): Trichoderma virens 2, c): Fusarium solani d) Fusarium oxysporum. (Source: Barasa, 2017)
mycelia
Plate 4.3: Infection by antagonistic fungus on thrip's cuticle; A: Trichoderma. afroharzianum, B: Trichoderma virens. (x 40 Mg). (Source: Barasa, 2017).
53
4.3. Effectiveness of fungal antagonists in management of F. occidentalis
on tomatoes in the field
At Bukonoi, in the long rainy cropping season (March-July, 2018), the mean number of F. occidentalis varied over weeks after transplanting of tomatoes. During the cropping season, the least mean number (1.0) of F. occidentalis was recorded on tomatoes in plots treated with F. oxysporum at 6th
WAT while the highest mean number (6.1) of F. occidentalis was observed on the control treatment at 7th WAT. A significant difference was observed on the seventh (F=4.48; df=7, 24; P=0.003) WAT but there were no significant differences on the sixth (F=2.34; df=7, 24; P=0.056), eighth (F=2.36; df=7, 24;
P=0.055), ninth (F=1.09; df=7, 24; P=0.399) and tenth WAT (F=1.02; df=7,
24; P=0.443) (Figure 4.5).
54
Beauveria bassiana Control (water) Fusarium oxysporum Trichoderma virens1 Imidacloprid Fusarium solani Trichoderma afroharzianum Trichoderma virens 2
8
7
6
5
per flower per
4
thrips
3
2 Mean number of number Mean 1
0 6 7 8 9 10 Weeks after transplanting (WAT)
Figure 4.5: Trend of Western flower thrips in tomatoes under different
fungal treatments during long rainy cropping season at
Bukonoi.
In the second short rainy cropping season (August-November, 2018), the difference in the mean number of F. occidentalis application was significant on the 6th WAT (F=3.92; df=7, 24; P=0.005), 8th WAT (F=3.19;
55 df=7, 24; P= 0.015), 9th WAT (F=7.46; df=7, 24; P<0.0001) and on 10th WAT
(F=9.25; df=7, 24; P<0.0001) (Figure 4.6).
Beauveria bassiana Control (water) Fusarium oxysporum Trichoderma virens1 Imidacloprid Fusarium solani Trichoderma afroharzianum Trichoderma virens 2
4 per flower
3 thrips 2
1
Mean Mean number of 0 6 7 8 9 10 Weeks after transplanting (WAT)
Figure 4.6: Trend of Western flower thrips in tomatoes under different
fungal treatments during short rainy cropping season at
Bukonoi.
All the fungal antagonists significantly (F=2.78; df=7, 24; P=0.028);
(F=18.32; df=7, 24; P<0.0001) reduced the mean number of F. occidentalis during the long rainy and short rainy cropping season, respectively in relation to the control treatment. Fusarium oxysporum was the most effective antagonist recording the least mean number (1.9) of F. occidentalis compared to the negative control which had the highest mean number of about 4.1 and
56
1.6 F. occidentals during the long rainy and short rainy cropping season, respectively. There was higher mean number of F. occidentalis in the long rainy cropping season (March - July, 2018) than during the short rainy crop season (August-November, 2018) (Table 4.9).
Table 4.9: Mean number ± S.E of F. occidentalis per flower on tomato
treated by different fungal species
Long rainy season Short rainy season
Treatment (March-July, 2018) (August-November, 2018)
Beauveria bassiana 2.7±0.4b 0.8±0.0d
Control (water) 4.1±0.7a 1.6±0.0a
Fusarium oxysporum 1.9±0.6b 0.9±0.1cd
Fusarium solani 2.2±0.3b 1.1±0.0bc
Imidacloprid 1.9±0.6b 0.9±0.1d
Trichoderma afroharzianum 2.2±0.1b 0.9±0.1cd
Trichoderma virens 1 2.2±0.2b 1.1±0.1b
Trichoderma virens 2 2.3±0.1b 0.9±0.1cd
P-value 0.028 <0.0001 df 7, 24 7, 24
F-value 2.78 18.32
Means followed by the same letter (s) in each column are not significantly different according to Student Newman-Keuls (SNK) test at P≤0.05.
57
At Cheptais, during the long rainy planting season (March-July, 2018), there was no significant difference in the mean number of F. occidentalis at the
6th WAT. However, significant differences were observed at week seven
(F=8.24; df=7, 24; P<0.0001), eight (F=12.18; df=7, 24; P<0.0001), nine
(F=5.47; df=7, 24; P=0.001) and at 10th WAT (F=4.97; df=7, 24; P=0.001)
(Figure 4.7).
Beaveria bassiana Control (water)
Fusarium oxysporum Trichoderma virens1
Imidacloprid Fusarium solani 9
Trichoderma afroharzianum Trichoderma virens 2 8
7 per flower per 6
thrips 5
4
3 umberof 2
Mean n Mean 1
0 6 7 8 9 10
Weeks after transplanting (WAT)
Figure 4.7: Trend of Western flower thrips in tomatoes under different
fungal treatments during long rainy cropping season at
Cheptais.
58
In the short rainy season (August-November, 2018), there was a significant difference in the mean numbers of F. occidentalis between the treatments on the 6th WAT (F=3.29; df=7, 24; P=0.013), 8th WAT (F=5.46; df=7, 24; P=0.0008), 9th WAT (F=6.59; df=7, 24; P=0.0002) and on 10th WAT
(F=5.79, df=7, 24; P=0.0005) (Figure 4.8).
Beaveria bassiana Control (water)
Fusarium oxysporum Trichoderma virens 1
Imidacloprid Fusarium solani
Trichoderma afroharzianum Trichoderma virens 2
4
3
per flower per
thrips
2 umber of umber
1 Mean n Mean
0 6 7 8 9 10
Weeks after transplanting (WAT)
Figure 4.8: Trend of Western flower thrips in tomatoes under different
fungal treatments during short rainy cropping season at
Cheptais.
59
All the antagonistic fungi significantly (F=34.24; df=7, 24; P<0.0001) reduced the mean number of F. occidentalis with the least (2.4) recorded on F. oxysporum treatment relative to the negative control which had the highest
(4.8) mean number of F. occidentalis during the long rainy cropping season
(Table 4.10).
In the short rainy cropping season, Trichoderma afroharzianum was the most effective antagonist recording the least mean number of (1.0) F. occidentalis compared to the negative control that recorded the highest mean number of about (1.8). As observed at Bukonoi, a higher mean number of F. occidentalis occurred in the long rain cropping season (March-July, 2018) than in the short rain cropping period (August-November, 2018) (Table 4.10).
60
Table 4.10: Mean number ± S.E of F. occidentalis per flower on tomato
recorded at Cheptais
Treatment Long rainy season Short rainy season
Beauveria bassiana 2.8±0.1bc 1.4±0.1b
Control (water) 4.8±0.1a 1.8±0.1a
Fusarium oxysporum 2.4±0.2c 1.0±0.1bcd
Fusarium solani 2.6±0.2bc 1.1±0.0bcd
Imidacloprid 1.4±0.1d 1.3±0.2bc
Trichoderma afroharzianum 2.4±0.1c 1.0±0.1d
Trichoderma virens 1 3.0±0.2b 1.4±0.2b
Trichoderma virens 2 2.5±0.2bc 1.0±0.1cd
P-value <0.0001 0.0006 df 7, 24 7, 24
F-value 34.24 5.65
Means with the same letter (s) within each column are not significantly different according to Student Newman-Keuls (SNK) test at P≤0.05.
At Bukonoi, in March-July, 2018 long rainy tomato cropping season, the total yield of tomatoes differed significantly (F=5.21; df=7, 24; P=0.001) as well as the marketable yield (F=3.28; df=7, 24; P=0.013) among the fungal treatments (Table 4.11). However, the yields were not significantly different during the August-November, 2018 short rainy cropping season (Table 4.12).
Trichoderma afroharzianum (Plate 4.2) had the highest mean marketable yield of tomatoes during both March-July and the August-November cropping 61 season recording 3.8 t/ha and 27.2 t/ha respectively, compared to the control
(Table 4.12 and 11, respectively). The yields were higher during the August-
November season than during the March-July growing season (Table 4.11).
Table 4.11: Mean yield (t/ha) ± S.E of tomatoes harvested at Bukonoi
during the long rainy season (March-July, 2018).
Treatment Total Marketable Unmarketable
Beauveria bassiana 4.4±1.9abc 3.3±1.7ab 1.0±0.2b
Control (water) 0.0±0.0d 0.0±0.0c 0.0±0.0e
Fusarium oxysporum 2.0±0.4cd 1.5±0.3bc 0.4±0.1de
Fusarium solani 3.4±0.4bc 2.6±0.4ab 0.8±0.1bc
Imidacloprid 6.9±0.5a 4.8±0.5a 2.1±0.1a
Trichoderma afroharzianum 4.8±0.9ab 3.8±0.9ab 0.8±0.2bc
Trichoderma virens 1 2.2±0.3bcd 1.8±0.3bc 0.5±0.1cd
Trichoderma virens 2 3.6±1.2bc 2.9±1.1ab 0.8±0.2bc
P-value 0.001 0.013 <0.0001 df 7, 24 7, 24 7, 24
F-value 5.21 3.28 23.64
Means followed by the same letter (s) in each column are not significantly different according to Student Newman-Keuls (SNK) test at P≤0.05.
62
Table 4.12: Mean yield (t/ha) ± S.E of tomatoes harvested at Bukonoi
during short rainy season (August-November, 2018).
Short rainy season (August-November, 2018)
Treatment Total Marketable Unmarketable
Beauveria bassiana 26.9±2.7ab 23.9±3.9ab 3.0±0.2a
Control (water) 18.1±1.9b 16.5±1.9b 1.7±0.2b
Fusarium oxysporum 26.8±3.0ab 24.3±2.8ab 2.6±0.5a
Fusarium solani 25.6±2.7ab 23.1±2.6ab 2.5±0.1a
Imidacloprid 28.1±4.4a 24.9±4.3ab 3.1±0.3a
Trichoderma afroharzianum 29.4±2.4a 27.2±2.4a 2.7±0.1a
Trichoderma virens 1 24.2±3.2ab 21.6±2.9ab 2.5±0.2a
Trichoderma virens 2 26.7±4.4ab 24.0±4.2ab 2.6±0.3a
P-value 0.367 0.432 0.041 df 7, 24 7, 24 7, 24
F-value 1.15 1.04 2.54
Means followed by the same letter (s) in each column are not significantly different according to Student Newman-Keuls (SNK) test at P≤0.05.
At Cheptais, during the March-July, 2018 long rainy cropping season, there was significant difference between the total yield (F=7.44; df=7, 24;
P<0.0001) and mean marketable yield (F=5.55; df=7, 24; P=0.0007) of tomatoes. Trichoderma virens 1 gave the highest total yield of about 0.8 t/ha compared to the negative control (Plate 4.5) which recorded zero yields (Table
63
4.13). In August-November, 2018 short rainy season, T. afroharzianum (Plate
4.4) recorded the highest mean marketable yield of about 12.8 t/ha (Table
4.14).
Table 4.13: Mean yield (t/ha) ± S.E of tomatoes harvested at Cheptais in
long rainy season (March-July, 2018).
Treatment Total Marketable Unmarketable
Beauveria bassiana 0.9±0.1b 0.5±0.1b 0.4±0.0b
Control (water) 0.0±0.0c 0.0±0.0c 0.0±0.0c
Fusarium oxysporum 0.6±0.2b 0.4±0.1bc 0.3±0.1b
Fusarium solani 0.7±0.2b 0.4±0.1b 0.3±0.1b
Imidacloprid 1.8±0.3a 1.1±0.3a 0.7±0.1a
Trichoderma afroharzianum 0.6±0.2b 0.3±0.1bc 0.3±0.1b
Trichoderma virens 1 0.8±0.0b 0.5±0.0b 0.3±0.0b
Trichoderma virens 2 0.7±0.1b 0.3±0.1bc 0.4±0.1b
P-value <0.0001 0.0007 <0.0001 df 7, 24 7, 24 7, 24
F-value 7.44 5.55 8.87
Means followed by the same letter (s) in each column are not significantly different according to Student Newman-Keuls (SNK) test at P≤0.05.
64
Table 4.14: Mean yield (t/ha) ± S.E of tomatoes harvested at Cheptais in
short rainy season (August-November, 2018).
Treatment Total Marketable Unmarketable
Beauveria bassiana 13.3±2.8a 10.5±2.1a 3.0±0.6a
Control (water) 9.7±1.2b 6.9±0.8b 2.7±0.4b
Fusarium oxysporum 15.8±3.9a 12.5±3.1a 3.3±0.8a
Fusarium solani 14.8±2.3a 11.3±1.8a 3.5±0.6a
Imidacloprid 15.6±2.8a 11.9±2.3a 3.7±0.6a
Trichoderma afroharzianum 17.8±1.3a 12.8±1.8a 3.0±0.5a
Trichoderma virens 1 13.7±5.3a 11.5±4.5a 2.2±0.8a
Trichoderma virens 2 18.1±3.8a 14.7±3.3a 3.1±0.4a
P-value 0.662 0.687 0.741 df 7, 24 7, 24 7, 24
F-value 0.71 0.68 0.61
Means followed by the same letter (s) in each column are not significantly different according to Student Newman-Keuls (SNK) test at P≤0.05.
65
A B
C D
E F
Plate 4.44: Tomatoes sprayed with fungal antagonists in the field trial A)
Control (water), B) T. afroharzianum, C) F. oxysporum, D) B.
bassiana (Commercial), E) T. virens 2., F) Imidacloprid (synthetic
pesticide).
(Source: Barasa, 2018)
66
CHAPTER FIVE: DISCUSSION
5.1 Occurrence of major arthropod pests of tomato in Bungoma County
5.1.1 Demographic characteristics of tomato farmers
The results revealed that majority of the respondents engaged in tomato cultivation across the three sub-Counties were men. This could be due to the fact that men control the most productive resources such as land in addition to capital. Angelina (2014) reported a similar outcome of males’ being majority in tomato production in Musoma Municipality, Tanzania. These findings are also consistent with previous studies in five counties in Kenya (Onduso, 2014;
Mwangi et al., 2015; Nguetti et al., 2018) and in Nigeria (Usman and Bakari,
2013).
Majority of the tomato farmers interviewed were between the ages of
41-45 years. This implied that the middle aged people who had much responsibility for their families were the ones more involved in the production of tomato as it seemed to be a feasible activity in Bungoma County. These results confirm studies in Tanzania by Angelina (2014) and in Mwea region,
Kenya by Nguetti et al. (2018) but contrast with the report by Anang et al.
(2013) and Mwangi et al. (2015) in Mwea West Sub-County, Kenya who found that most of tomato growers were young and aged between 21 to 40 years.
Most of the farmers interviewed had primary education level. This shows that majority of primary school leavers who could not continue with further education could have joined farming as a source of their livelihood
67
(Haleegoah et al., 2013; URT, 2014). However, in Bumula and Mt. Elgon, majority of respondents had secondary education. This is vital in understanding the management practices, for tomato production. Farmers in the area may easily adopt improved farming practices as they can fully comprehend the implications of such practices. Literacy is an important characteristic that influences agricultural production (Awan et al., 2012).
The findings showed that the respondents had farm sizes ranging from
0.25 to 2.0 ha with the majority owning between 0.25 and 1.0 ha. This agrees with Karuku et al. (2016) who reported that smallholder farmers owned less than 2.0 ha of land. The results indicated that most of the respondents had been active in tomato cultivation for over 5 years while the rest had experience of up to five years or less. This implied that tomato production is of great importance in Bungoma County and the farmers are well knowledgeable on production challenges. These findings are in agreement with previous reports by Wachira et al. (2014) in a study conducted in Nakuru and Ongwae (2016) in Taita
Taveta who found that the mean number of tomato farming experience was about 11 years.
5.1.2 Tomato varieties grown by farmers in Bungoma County
It was observed that Rio-Grande, Cal-J and Elgon Kenya were the preferred tomato cultivars grown by farmers in the County due to their longer shelf life. The farmers were also embracing new cultivars of tomatoes such as
Kilele, Safari and Ana F1 which are documented as high yielding and resistant
68
to diseases (Monsanto, 2017). Mwangi et al. (2015) reported similar findings in
Mwea West Sub-County where farmers grew a wide range of tomato varieties.
5.1.3 Arthropod pests and diseases affecting tomato production in
Bungoma County
A complex of arthropod pests and diseases were reported across the
three sub-counties. This could be due to the agro-ecological conditions that
favor the occurrence of the pests and diseases, farmers’ practices such as
continuous cropping of tomato and cultivation of seed varieties that could be
susceptible to pest and disease attack. These findings are in agreement with
other studies by Mueke (2014) and Omondi (2015) in Kirinyaga County,
Kenya. The high incidence of Ralstonia solanacearum disease across the three
sub-counties implied that the disease was widespread and challenging to
control. These results agrees with earlier reports by Mwangi et al. (2015) and
Kanyua (2018) who reported the long term persistence of the disease in the soil
and wide spread in many infested tomato fields in Kenya.
5.1.4 Management of arthropod pests and diseases of tomato in Bungoma
County
It was noted that the farmers used Imidacloprid, Lamda-Cyhalothrin
and mancozeb synthetic chemicals on tomato production. However, these
chemicals have been reported to be toxic to non-target beneficial organisms
such as bees, fish and natural enemies of arthropod pests such as the lady bird
beetle Coccinella septempunctata Latreille (Coleoptera: Coccinellidae)
(Ndakidemi et al., 2016). All respondents in Sirisia applied chemicals once on
69 weekly basis. This could be due to belief that frequent application and mixing of different chemicals could effectively control the pests and diseases as reported by Asif et al. (2014). This frequent application of synthetic chemicals could lead to pests developing resistance to chemicals as well as increased costs of production (Mollah et al., 2013). The results of this study concurs with the previous findings by other researchers (Njogu et al., 2013; Mutuku et al.,
2014; Tinyami et al., 2014; Nguetti et al. (2018) who reported frequent application of synthetic chemicals on tomato production.
There were variations in the responses on the effectiveness of the chemicals applied by the farmers in tomato production. This could be due to difference in the frequency of chemical application on tomato production and the target pests (Tarla et al., 2015). Majority of the respondents were unfamiliar with the application of biological control agents in management of tomato pests. This could be due to lack of information and awareness on alternatives to chemical pesticides as majority of respondents sourced advice on pesticide use from agrovet shop operators who may not be well informed with IPM strategies. These results correspond with those reported by Asif et al.
(2014) in Lower Sindh Pakistan who found that farmers relied on pesticide dealers for advice on chemical use. This has also been reported in Kirinyaga
County, Kenya by Onduso (2014).who observed that advice from farm input shops (Agrovets) ranked top (45%) as a key source of information for farmers on pests and disease management on tomato production.
70
5.2 Evaluation of insecticidal activity of antagonistic fungi in biological
control of F. occidentalis in vitro
The results revealed that majority of the fungal species from the soil samples belonged to the genera Trichoderma. These included T. afroharzianum
T. harzianum, T. koningi, T. pseudokoningi and T. aureoviride. Other studies have confirmed abundance of this fungus in soil samples collected from Busia and Upper Kabete, Kenya (Fulano, 2016; Muthomi et al., 2017).
All the fungal antagonists evaluated were pathogenic to both adults and nymphs of F. occidentalis. The adults were more infected by the fungal isolates than nymphs. This could partly be attributed to the loss of fungal conidia in the nymphs during ecdysis (Niassy et al., 2012). Mortality levels varied significantly between the isolates which concur with previous report by Wu et al. (2014). Of the five best performing isolates, T. virens has earlier been found to be most virulent in the control of Triatoma dimidiata Latreille (Hemiptera:
Reduviidae) which caused about 100% and 35.7% mortality in the adults and nymphs, respectively (Guadalupe et al., 2014). This high virulence of T. virens fungus was confirmed in this study.
5.3. Effects of fungal antagonists on management of F. occidentalis on
tomato
The mean number of F. occidentalis varied over time during the flowering period in all treatments with highest mean number recorded in the control treatment. However, the mean number of F. occidentalis did not increase over time in the control treatment. This may be due to reduced number
71 of flowers formed over time as the crop entered fruiting stage (Luis et al.,
2015). This is also in accordance with the studies by Nyasani et al. (2013) and
Nyasani et al. (2015) who worked on French beans Phaseolus vulgaris L., and reported a stable increase in the mean number of F. occidentalis over time to the maximum followed by a decrease as the crop reached maturity stage.
There was higher mean number of F. occidentalis recorded during the long rainy cropping season than in the short growing season. This could be due to the cryptic behavior of F. occidentalis as they prefer to aggregate inside flowers and concealed spaces of plants during wet seasons and adult females forage on pollen to enhance initiation of egg laying, fasten development of the larvae and increasing female fertility (Reitz, 2009; Nandwa, 2013; Muthomi et al., 2017).
High temperatures experienced during the March-July rainy season than the August- November short rainy season could also have led to the high population of F. occidentalis recorded in long rainy season (Breno et al.,
2019). However, our results differed with the study by Bikash (2013) and
Ssemwogerere et al. (2013) who reported that F. occidentalis population was highest on tomato during the short rainy season than the long rainy season.
This difference could be due to weather conditions such as temperature, rainfall and relative humidity which are important factors regulating pests populations in crops (Semeao et al., 2012). Rainfall may have both negative and positive effects on insect population density. In a negative way, high rainfall causes insect death due to the mechanical impact of droplets which wash away the small insects onto the soil. High relative humidity also increases insect
72 mortality due to entomopathogenic fungi infection (Augustyniuk-Kram and
Kram, 2012). Indirectly, high rainfall may enhance luxuriant growth of plants which become a food resource to arthropod pests (Semeao et al., 2012). This is what was observed to F. occidentalis in our field experiments.
The fungal antagonists reduced the populations of F. occidentalis with
Fusarium oxysporum and T. afroharzianum being most effective. These results concur with those of Lakhdari et al. (2016) who reported insecticidal effects of
F. oxysporum in reducing infestation of Tuta absoluta on tomato. The outcomes of this study are also in line with previous studies by Fulano (2016) and Lengai (2016) who reported the effectiveness of Trichoderma spp. on management of F. occidentalis, B. tabaci and Tuta absoluta.
Higher yields were recorded during the short rainy season than in the long rainy season. This could be due to low numbers of F. occidentalis recorded on flowers during the short rainy cropping season than the long rainy season which could have led to minimal flower abortion thus increased yields
(Infonet-biovision, 2019). These findings corroborate previous studies that have illustrated reduced populations of arthropod pests by application of fungal antagonists with remarkable increase in tomato yield (Shafie and Abdelraheem,
2012; Lengai, 2016).
The results of this study showed that T. afroharzianum was more effective in reducing the population of F. occidentalis and it also increased the marketable yield of tomatoes in both long and short rainy cropping seasons compared to the control treatment. These findings are in agreement with
Muthomi et al. (2017) who reported significantly higher pod yield of French
73 beans after foliar application of Trichoderma spp. in management of pests and diseases. The observed results that T. afroharzianum increased yield of tomatoes can also be attributed to its ability in promoting growth of plants as well as inducing resistance to pathogens (Mwangi et al., 2009; Sawant, 2014).
74
CHAPTER SIX: CONCLUSIONS AND RECOMMENDATIONS
6.1: Conclusions
i. Survey results revealed that a wide range of arthropod pests constraints
tomato production in Bungoma County with thrips (Frankliniella
occidentalis) being the major pest.
ii. The results showed that five fungal antagonists T. afroharzianum, F.
oxysporum, T. virens 1, F. solani and T. virens 2 were the most
pathogenic to nymphs and adult stage of F. occidentalis; although with
varying mortality levels.
iii. The findings of this study demonstrated that F. oxysporum and T.
afroharzianum were most effective in reducing the population of F.
occidentalis on tomato as well as increasing yield of tomatoes under
field conditions.
6.2: Recommendations
i. Studies should be conducted to determine the population dynamics of
major arthropod pests of tomato in Bungoma County. This will be
helpful in developing suitable pest management practices.
ii. Further exploitation and screening of microbial antagonists of arthropod
pests from the local environment should be encouraged.
iii. The study recommends that F. oxysporum and T. afroharzianum have
potential for development as fungal-based bio-pesticides for
management of F. occidentalis on tomato as an alternative to synthetic
pesticides. More research should be done to identify the active
compounds of these fungal antagonists. This will be helpful in their
75 formulation and subsequent commercialization as bio-pesticides.
Further research should be done to determine the optimal conditions for effectiveness of F. oxysporum and T. afroharzianum.
76
REFERENCES
Abu, A. B. A. and El-Hindi, M. W. (2017). Isolation, Molecular Identification
and under Lab Evaluation of the Entomopathogenic Fungi M.
anisopliae and B. bassiana against the Red Palm Weevil R. ferrugineus
in Gaza Strip. Advances in Microbiology, 7: 109-124.
Afreen, S., Rahman, M. M., Islam, M. M. U., Hasan, M. and Islam, A. K. M. S.
(2017). Management of insect pests in tomato Solanum lycopersicum L.
under different planting dates and mechanical support. Journal of
Science, Technology and Environment Informatics, 5(1): 336-346.
Akrami, M. and Yousefi, Z. (2015). Biological control of Fusarium wilt of
tomato (Solanum lycopersicum) by Trichoderma spp. as antagonist
fungi. Biological Forum-An International Journal, 7(1): 887-892.
Alexandrov, V. (2011). Efficacy of some fungicides against late blight of
tomato, Bulgarian. Journal of Agricultural Sciences, 1(4): 465-469.
Anang, B. T., Zulkarnain, A. Z. and Yusif, S. (2013). Production constraints
and measures to enhance the competitiveness of tomato industry in
Wenchi Municipal District of Ghana. American Journal of
Experimental Agriculture, 3(4): 824-838.
Angelina, W. M. (2014). Assessment of socio-economic and institutional
factors influencing tomato productivity amongst smallholder farmers: a
case study of Musoma Municipality, Tanzania. MSc. Thesis. Sokoine
University of Agriculture, Morogoro, Tanzania.
77
Asante, B., Osei, M., Dankyi, A., Berchie, J., Mochiah, M., Lamptey, J.,
Haleegoah, J., Osei, K. and Bolfrey-Arku, G. (2013). Producer
characteristics and determinants of technical efficiency of tomato based
production systems in Ghana. Journal of Development and Agricultural
Economics, 5(3): 92-103.
Ashour, A. M. A. (2009). A protocol suggested for managing tomato early
blight, Egypt. Journal of Phytopathology, 37(1): 9-20.
Asif, A., Jamali, A. R. S., Najma, M. and Shafi, M. N. (2014). Current scenario
of pesticide practices among farmers for vegetable production: A case
study in Lower Sindh, Pakistan. International Journal of Development
and Sustainability, 3(3): 493-504.
Augustyniuk-Kram, A. and Kram, K. J. (2012). Entomopathogenic fungi as an
important natural regulator of insect outbreaks in forests. A review.
Forest Ecosystems, 265-294.
Awan, S. M., Hussain, A., Abbas, T. and Karamu, R. (2012). Assessment
of production Practices of small scale farm holders of tomato in Bagrote
Valley, CKNP region of Gilgit-Baltistan, Pakistan. Acta Agriculture
Slovenica, 99(2): 191-199.
Azandeme-Hounmalon, G .Y., Fellous, S., Kreifer, S., Fiaboe, K. K. M. and
Subramanian, S. (2014). Dispersal of Tetranychus evansi and T. urticae
on tomato at several spatial scales and densities: implications for
integrated pest management. PloS ONE, 9(4): 18-24.
78
Bacci, L., Silva, E. M., Martins, J. C., Soares, M. A., Campos, M. R. and
Picanco, M. C. (2019). Seasonal variation in natural mortality factors of
Tuta absoluta (Lepidoptera: Gelechiidae) in open-field tomato
cultivation. Journal of Applied Entomology, 143: 21-33.
Barasa, M. W., Kahuthia-Gathu, R., Mwangi, M. and Wackeke, J. W. (2019).
Tomato Production Characteristics, Biotic constraints and their
Management Practices by Farmers in Bungoma County, Kenya. Journal
of Natural Sciences Research, 9(12): 46-55.
Bayissa, W., Ekesi, S., Mohamed, S. A., Kaaya, G. P., Wagacha, J. M., Hanna,
R. and Maniania, N. K. (2017). Selection of fungal isolates for
virulence against three aphid pest species of crucifers and okra. Journal
of Pest Science, 90(1): 355-368.
Belete, E., Ayalew, A. and Ahmed, S. (2015). Evaluation of local isolates of
Trichoderma spp. against black root rot Fusarium solani on Faba bean.
Journal of Plant Pathology and Microbiology, 6: 279-284.
Bhattacharjee, R. and Dey, U. (2014). An overview of fungal and bacterial
biopesticides to control plant pathogens and diseases. African Journal
of Microbiology Research, 8(7): 1749-1769.
Bikash, S. (2013). Studies on the pest complex of tomato Lycopersicon
esculentum L. and their sustainable management. MSc. Thesis. Uttar
Banga Krishi Viswavidyalaya in West Bengal, India.
79
Bollmohr, S. and Liebetrau, L. (2019). Banned pesticide use in Kenya-an
urgent need to move towards sustainable agriculture. First International
Conference on Agroecology Transforming Agriculture and Food
Systems in Africa, June 18th-21st, 2019, Safari Park Hotel and Casino,
Nairobi, Kenya.
Boote, D. K., Araujo, W. L., Nick, C. and Handa, P. A. K. (2017). Achieving
sustainable cultivation of tomatoes. International Journal of Crop
Protection, 15: 23-35.
Borisade, O. A. and Magan, N. (2015). Growth and sporulation of
entomopathogenic Beauveria bassiana, Metarhizium anisopliae, Isaria
farinosa and Isaria fumosorosea strains in relation to water activity and
temperature interactions. Journal of Bio-control Science and
Technology, 24(9): 999-1011.
Breno, G. B., Renato, A. S., Poliana, S. P. and Marcelo, C. P. (2019). Factors
affecting thrips (Thysanoptera: Thripidae) population densities in
Watermelon crops. BioOne, 102(1): 10-15.
Bungoma County Integrated Development Plan. (2013). County Integrated
Development Plan 2013-2017. County Government of Bungoma.
Castilho, A. M. C., Fraga, M. E. and Mora, M. A. E. (2018). Classification and
infection mechanism of entomopathogenic fungi. Journal of
Agricultural Microbiology, 4: 84.
Chaudhary, P., Sharma, A., Singh, B. and Nagpal, A. K. (2018). Bioactivities
of phytochemicals present in tomato. Journal of Food Science and
Technology, 55(8): 2833-2849.
80
Cherif, A., Mansour, R. and Grissa-Lebdi, K. (2013). Biological aspects of
tomato leaf miner Tuta absoluta (Lepidoptera: Gelechiide) in
conditions of North Eastern Tunisia: possible implications for pest
management, Environmental and Experimental Biology, 11: 179-184.
Chethana, B. S., Ganeshan, G., Rao, A. S. and Bellishree, K. (2012). In vitro
evaluation of plant extracts, bioagents and fungicides against Alternaria
porri (Ellis) causing purple blotch diseases of onions. Pest Management
in Horticultural Ecosystems, 18(2): 194-198.
Chung, S. W. C. (2018). How effective are common household preparations on
removing pesticide residues from fruit and vegetables?. Journal of the
Science of Food and Agriculture, 98(8): 2857-2870.
Civolani, S., Boselli, M., Butturini, A., Chicca, M., Fano, E. A. and Cassanelli,
S. (2014). Assessment of Insecticide Resistance of Lobesia botrana
(Lepidoptera: Tortricidae) in Emilia-Romagna Region. Journal of
Economic Entomology, 107(3): 1245-1249.
Degri, M. M. and Samaila, A. E. (2014). Impact of intercropping tomato and
maize on the infestation of tomato fruit borer Helicoverpa armigera
(Hubner). Journal of Agricultural and Crop Research, 2(8): 160-164.
Demirozer, O., Tyler-Julian, K. and Leppla, N. (2014). Integrated pest
management program for thrips and Tospoviruses in fruiting
vegetables. Pest Management Science, 68(12): 1537–15458.
Derrico, G., Giacometti, R., Roversi, P. F., Prasad, L. and Woo, S. L. (2016).
Root knot disease caused by Meloidogyne incognita on tomato grown
in soil-less culture in Italy. Journal of Zoology, 99: 25-28.
81
Durmusoglu, E., Hatipoglu, A., Gurkan, M. O. and Moores, G. (2015).
Comparison of different bioassay methods for determining insecticide
resistance in European Grapevine Moth, Lobesia botrana (Denis)
(Lepidoptera: Tortricidae). Turkish Journal of Entomology, 39(3): 271-
276.
Eliska, O. (2015). The use of entomopathogenic fungi in biological control of
pests. Journal of Entomology, 18: 102-105.
Engindeniz, S. and Ozturk, G. C. (2013). An economic comparison of pesticide
Application for processing and table tomatoes, a case study for Turkey.
Journal of Plant Protection Research, 53(3): 230-237.
Enver, D., Ahmet, H., Oktay, G. and Graham M. (2015). Comparison of
different bioassay methods for determining insecticide resistance in
European Grapevine Moth, Lobesia botrana (Denis) (Lepidoptera:
Tortricidae). Turkish Journal of Entomology, 39(3): 271-276.
Espinosa-Juarez, J. V., Colado-Velazquez, J. I. I. I., Mailloux-Salinas, P.,
Medina-Contreras, J. M. L., Correa-Lopez, P. V., Meza-Cuenca, F. and
Bravo, G. (2017). Beneficial effects of lipidic extracts of saladette
tomato pomace and Serenoa repens on prostate and bladder health in
obese male Wistar rats. Journal of the Science of Food and Agriculture,
97(13): 4451-4458.
Estefania, R., Mar, M. T. and Dirk, J. (2019). Whitefly Control Strategies
against Tomato Leaf Curl. New Delhi Virus in Greenhouse Zucchini.
International Journal of Environmental Research and Public Health, 16:
1-12.
82
Fajinmi, A. A. and Fajinmi, O. B. (2010). An overview of Bacterial wilt
disease of tomato in Nigeria. Agricultural journal, 5(4): 242-247.
FAO. (2018). Food and Agricultural Organization of the United Nations
Faostatstatisticsdatabase.11/02/2019http://www.fao.org/faostat/en/#dat/
QCProduction of selected vegetable crops.
Fedai, E. and Ozgur A. A (2015). Potential of two entomopathogenic fungi,
Beauveria bassiana and Metarhizium anisopliae (Coleoptera:
Scarabaeidae), as biological control agents against the June beetle.
Journal of Insect Science, 15(1): 44-57.
Fentik, D. A. (2017). Review on Genetics and Breeding of Tomato
(Lycopersicum esculentum Mill). Advances in Crop Science and
Technology, 5: 5.
Fulano, A. M. (2016). Management of pests and diseases in snap beans by use
of microbial antagonists and plant extracts. MSc. Thesis. University of
Nairobi, Kenya.
Gacheri, V. K. (2016). Effects of coloured agronets in the management of
tomato (Solanum lycopersicum L.) pests and tomato yield in Kenya.
MSc. Thesis. Kenyatta University, Kenya.
Gao, Y. L., Reitz, S. R. and Wang, E. D. (2012). Potential use of the fungus
Beauveria bassiana against the Western thrips Frankliniella
occidentalis without reducing the effectiveness of its natural predator
Orius sauteri (Hemiptera: Anthocoridae). Journal of Biocontrol Science
and Technology, 22: 803–812.
83
Ghais, Z., Ibrahim, S. and Angham, B. (2013). Life History Parameters of the
Tomato Red Spider Mite Tetranychus evansi (Acari: Tetranychidae),
Collected in Syria, on Two Solanaceous Plants. ACARINES, 7(2): 71-
76.
Giorgini, M., Guerrieri, E., Cascone, P. and Gontijo, L. (2019). Current
Strategies and Future Outlook for Managing the Neotropical Tomato
Pest Tuta absoluta (Meyrick) in the Mediterranean Basin. Neotropical
Entomology, 48(1): 1-17.
Goda, N. F., El-Heneidy, A. H., Djelouah, K. and Hassan, N. (2015).
Integrated Pest Management of the Tomato Leaf Miner, Tuta absoluta
(Meyrick) (Lepidoptera: Gelechiidae) in Tomato Fields in Egypt.
Egyptian Journal of Biological Pest Control, 25(3): 655-661.
Goettel, M. S. and Inglis, D. G. (1997). Fungi Hypomycetes. In: Lacey L.
(eds). Manual of Techniques in Insect Pathology, 213-250.
Goufo, P., Mofor, T. C., Fontem, D. A. and Ngnokam, D. (2008). High
efficacy of extracts of cameroon plants against tomato late blight
disease. Agronomy for Sustainable Development, 28(4): 567-573.
Guadalupe, M., Blanca, E., Jose, L. T., and Mario, H. R. (2014). Potential for
entomopathogenic fungi to control Triatoma dimidiata (Hemiptera:
Reduviidae), a vector of Chagas disease in Mexico. Revista da
Sociedade Brasileira de Medicina Tropical, 47(6): 716-722.
Gupta, S., Singh, G. and Sharma, N. (2014). In vitro screening of selected plant
extracts against Alteraria alternata. Journal of Experimental Biology
and Agricultural Sciences, 2(3): 344-351.
84
Hackshaw-McGeagh, L. E., Perry, R. E., Leach, V. A., Qandil, S., Jeffreys, M.,
Martin, R. M. and Lane, J. A. (2015). A systematic review of dietary,
nutritional, and physical activity interventions for the prevention of
prostate cancer progression and mortality. Cancer causes and control.
International Journal of Studies of Cancer in Human Populations,
26(11): 1521-1550.
Hazewindus, M., Haenen, G. R., Weseler, A. R. and Bast, A. (2014). Protection
against chemotaxis in the anti-inflammatory effect of bio-actives from
tomato ketchup. Plos One, 9: 12-17.
Horticultural Crops Development Authority. (2018). HCDA -Horticulture
validated report. http://www.faostat.fao.org. Accessed on 21/03/2020.
Infonet-biovision (2019).Tomatoes,
http://www.infonetbiovision.org/default/ct/80/pests/diseases. Accessed
on 20/11/2019.
Ireri, D. F., Murungi, L. K., Ngeno, D. C. and Mbaka, J. (2018). Farmer
knowledge of bacterial wilt and root-knot nematodes and practices to
control the pathogens in high tunnel tomato production in the tropics.
International Journal of Vegetable Science, 1-13.
Jaetzold, R., Hornetz, B. and Schmidt, H. (2012). Farm Management
Handbook of Kenya. Volume. I-IV (Western, Central, Eastern, Nyanza,
Southern Rift Valley, Northern Rift Valley, Coast), Nairobi.
85
Jayasinghe, G. G. and Mallik, B. (2013). Growth stage based economic injury
levels for two spotted spider mite, Tetranychus urticae Koch (Acari,
Tetranychidae) on tomato, Lycopersicon ecsulentum Mill. Tropical
Agricultural Research, 22(1): 54-65.
Junior, J. B. T., Rezende, R., Itako, A. T., Freitas, P. S. L. and Frizzone, J. A.
(2011). Drip fungigation in early blight control of tomato. Maringa,
33(1): 9-14.
Kalyebi, A., Overholt, W. A., Schulthess, F, Mueke, J. M., Hassan, S. A. and
Sithanantham, S. (2015). Functional response of six indigenous
Trichogrammatid egg parasitoids (Hymenoptera: Trichogrammatidae)
in Kenya: influence of temperature and relative humidity. Journal of
Biological Control, 32: 164-171.
Kanyua, S. I. (2018). Evaluation of grafting technology for management of
Bacterial wilt (Ralstonia solanacearum) of tomato (Solanum
lycopersicum L.). MSc. Thesis. Kenyatta University, Kenya.
Karuku, G. N., Kimenju, J. W. and Verplancke, H. (2016). Farmers'
Perspectives on factors limiting tomato production and yields in
Kabete, Kiambu County, Kenya. East African Agricultural and Forestry
Journal, 82(1): 70-89.
Khan, S., Guo, L., Miaimaiti, M. M. and Qui, D. (2012). Entomopathigenic
fungi as microbial biocontrol agent. Journal of Molecular Plant
Breeding, 3: 63–79.
86
Kimani, V. (2014). Biopesticides development, use and regulation in Kenya.
Regional experts workshop on development, regulation and use of
biopesticide in East Africa . Slide share. Accessed on 21/12/2019.
Kithure, J. G. N., Murungi, J. I., Wanjau, R. N. and Thoruwa, C. L. (2014).
Analysis of Deltamethrin Residue Amounts Using HPLC in Some
Vegetables Consumed in a Rural Area - Makuyu, Kenya. The
International Journal of Science and Technology, 2(12): 279-284.
Konje, C. N., Abdulai, A. N., Achiri, D. T., Nsobinenyui, D., Tarla, D. N. and
Awah, M. T. (2019). Identification and Management of Pests and
Diseases of Garden Crops in Santa, Cameroon Journal of Agriculture
and Ecology Research International, 18(2): 1-9.
Kumar, K. R. (2013). Bio-efficacy and residue Dynamics of insecticides
Against fruit borer (Helicoverpa armigera Hub.) in tomato
(Lycopersicon esculentum Mill.). MSc. Agriculture Entomology Thesis,
submitted to Acharya, Ranga Agricultural University.
Kumar, S., Thakur, M. and Rani, A. (2014). Trichoderma: Mass production,
formulation, quality control, delivery and its scope in
commercialization in India for the management of plant diseases.
African Journal of Agricultural Research, 9 (53): 3838-3852.
Lakhdari, W., Dehliz A., Acheuk, F., Mlik, R., Hammi, H. and
Matallah, S. (2016). Biocontrol test against the leaf miner of tomato
Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) by using
entomopathogenic fungi in the Algerian Sahara. Journal Algerien des
Regions Arides (JARA), 13: 85-89.
87
Larki, J., Kilochyckij, P., Fedorenko, V. and Chumak, V. (2012). Interaction of
trap colour attractiveness with morphological variability of the thrips
Frankliniella occidentalis (Pergande). Archives of Phytopathology and
Plant Protection, 45: 499-504.
Lengai, W. M. G. (2016). Efficacy of plant extracts and antagonistic fungi as
alternatives to synthetic pesticides in management of tomato pests and
disease. MSc. Thesis. University of Nairobi, Kenya.
Lienneke, E. B., Ventje, M. and Trina, E. T. (2017). Monitoring of species and
population of important insect pest of tomato plants using yellow sticky
trap during conventional and integrated pest management system.
Journal of Animal and Plant Sciences, 34(1): 5404-5412.
Luis, A. T. P., Nestor, B. M., Roberto, J., Jesus, R. N. and Obdulia, S. L.
(2015). Population Fluctuations of Thrips (Thysanoptera) and Their
Relationship to the Phenology of Vegetable Crops in the Central
Region of Mexico Florida Entomologist, 98(2): 430-438.
Macharia, I., Backhouse, D., Skilton, R., Ateka, E., Wu. S. B., Njahira, M.,
Maina, S. and Harvey, J. (2015). Diversity of thrips species and vectors
of tomato spotted wilt virus in tomato production systems in Kenya.
Journal of Economic Entomology, 108: 20-28.
Mahmood, I., Imadi, S. R., Shazadi, K., Gul, A. and Hakeem, K. R. (2016).
Effects of Pesticides on Environment. Journal of Environmental
Science, 11: 253-269.
88
Mallikarjun, Y. and Kenganal, B. (2008). Farmers Note book on management
of Bacterial wilt in tomato.
www.Hindu.com/seta/2008/12104/stories/2008120450151500.htm.
Retrieved 2/4/2019.
Manikandan, R. and Raguchander, T. (2014). Prevalence of tomato wilt disease
incited by soil borne pathogen Fusarium oxysporum f.sp.lycopersici
(Sacc.) in Tami Nadu. International Journal of Tropical Agriculture,
32(1): 279-283.
Marabi, R. S., Das, S. B., Bhowmick, A. K., Pachori, R. and Vibha, S. H. L.
(2017). Seasonal population dynamics of whitefly (Bemisia tabaci
Gennadius) in soybean. Journal of Entomology and Zoology Studies,
5(2): 169-173.
Marek, B. (2010). Pathogenicity assessment of entomopathogenic fungi
infecting Leptoglossus occidentalis (Heteroptera: Coreidae). Journal of
Mycology, 62(1): 67-78.
Masoud, L. and Bahar, R. (2012). Pathogenicity of the entomopathogenic fungi
Beauveria bassiana and Metarhizium anisopliae to adult Oryctes
elegans and effects on feeding and fecundity. International Journal of
Crop Protection, 4: 1026-1032.
Mattoo, A. and Handa, A. (2017). Achieving sustainable cultivation of
tomatoes. Journal of Plant Pathology, 67(1): 252-252.
Melese, W. and Samul, S. (2018). Review on Disease Management Practice of
Tomato Wilt caused by Fusarium oxysporum in Case of Ethiopia.
Journal of Plant Pathology and Microbiology, 9: 11-18.
89
Merve, T. M., Beekwilder, J., Hall, R. D., Sagdic, O., Boyacioglu, D.,
Capanoglu, E. (2017). Industrial processing versus home processing of
tomato sauce: effects on phenolics, flavonoids and in vitro bio-
accessibility of antioxidants. Food Chemistry, 220: 51–58.
Mollah, M. I., Rahman, M. and Alam, Z. (2013). Effect of Insecticides on Lady
Bird Beetle (Coleoptera: Coccinellidae) in Country Bean Field. Middle-
East Journal of Scientific Research, 17: 1607-1610.
Mondal, S., Baksi, S., Koris, A. and Vatai, G. (2016). Journey of enzymes in
entomopathogenic fungi. Pacific Science Review A: Natural Science
and Engineering, 18(2): 85-99.
Monsanto website. (2017). Tomato Hand book.
http://www.monsantoafrica.com/_pdfs/tomato_growers hand
book.pdf.
Moritz, G., Brandt, S. and Subramanian, S. (2013). Identification and
information tools for pest thrips in East Africa. QAAFI Biological
Information Technology (QBIT). University of Queensland: Brisbane,
Australia, 3(4): 32-39.
Mueke, P. M. (2014). Insect pest incidences and yields of tomatoes grown in
high tunnel and in open field in Mwea Sub-County, Kirinyaga County,
Kenya. MSc. Thesis. Kenyatta University, Kenya.
Mugao, G. L. (2015). Tomato post-harvest spoilage, causes and use of selected
botanical extracts in their management in Mwea, Kirinyaga county.
MSc. Thesis. Kenyatta University, Kenya.
90
Mustafa, U. and Kaur, G. (2009). Extracellular enzyme production in
Metarhizium anisopliae isolates. Folia Microbiologica, 54(6): 499–
504.
Muthomi, J. W., Fulano, A. M., Wagacha, J. M. and Mwang’ombe, A. W.
(2017). Management of Snap Bean Insect Pests and Diseases by Use of
Antagonistic Fungi and Plant Extracts. Journal of Sustainable
Agriculture Research, 6(3): 52-63.
Mutuku, M., Njogu, P. and G. Nyagah. (2014). Assessment of the Current
Patterns and Practices of use of Pesticides in Tomato Based
Agrosystem in Kaliluni, Kathiani Constituency, Kenya. International
Journal of Soil, Plant and Environmental Science, 1(1): 10-15.
Mwangi, M. W., Ethel, O. M., Sheila, A. O. and Joyce, M. J. (2009). Effect of
Trichoderma harzianum and arbuscular mycorrhizal fungi on growth in
tomato (Lycopersicum esculentum Mill) Seedlings, napier (Pennisetum
purpureum L.) and tea (Camellia sinensis L.) cuttings. Tropical and
Subtropical Agroecosystems, 11: 423–429.
Mwangi, M. W., Mwangi, J. W., Kimenju, R. D., Narla, Kariuki, G. M. and
Muiru, W. M. (2015). Tomato Management Practices and Diseases
Occurrence in Mwea. Journal of Natural Sciences Research, 5(20):
2224-3186.
Mwangi, M. W., Kimenju, J. W., Narla, R. D. and Kariuki, G. M. (2017).
Evaluation of selected tomato cultivars reaction to infestation with
Meloidogyne javanica in greenhouse conditions. International Journal
of Agronomy and Agricultural Research, 11(3): 17-25.
91
National Farmers Information Service (NAFIS). (2018). Ecological
requirements,http://www.nafis.go.ke/vegetables/tomatoes/ecological-
requirements/accessed 2/02/2019.
National Initiative on Climate Resilient Agriculture (NICRA) team of pest
Surveillance. (2012). Manual for tomato pest surveillance, jointly
published by National Centre for Integrated Pest management
(NCIPM), New Delhi, Central Institute for Dry land Agriculture,
Hyderabad, Indian Institute for Horticultural Research, Bengaluru and
Indian Institute of Vegetable Research, Varanasi, 39-43.
Nagamandla, R. S., Shantanu, J. and Nagulapally, S. L. (2017). Insect Pests of
Tomato and Their Weather Relations under Open and Cover
Cultivation. International Journal of Current Microbiology and Applied
Sciences, 6(9): 368-375.
Nandwa, M. K. (2013). Effect of temperature on the efficacy of Metarhizium
anisopliae (Metchnikoff) Sorokin in the control of western flower thrips
in French beans. MSc. Thesis. University of Nairobi, Kenya.
Nashwa, S. M. A. and Abo-Elyousr, A. M. K. (2012). Evaluation of various
plant extracts against the early blight disease of tomato plants under
green house and field conditions. Plant Protection Science, 48(2): 74-
79.
Nassiuma, D. K. (2000). Survey Sampling: Theory and Methods. Njoro,
Kenya: Egerton University Press.
92
Ndakidemi, H., Kilinçer, N. and Ozkan, C. (2016). Toxicity and repellent
effects of some botanical insecticides on the egg-larval parasitoid
Chelonus oculator (Hymenoptera: Braconidae). Scientific Research and
Essays, 9: 106-113.
Ndereyimana, A., Nyalala, S., Murerwa, P. and Gaidashova, S. (2019).
Pathogenicity of some commercial formulations of entomopathogenic
fungi on the tomato leaf miner Tuta absoluta (Meyrick) (Lepidoptera:
Gelechiidae). Egyptian Journal of Biological Pest Control, 29(1): 1-5.
Nguetti, J. H., Imungi, J. K., Okoth, M. W., Wang’ombe, J., Mbacham, W. F.
and Mitema, S. E. (2018). Assessment of the knowledge and use of
pesticides by the tomato farmers in Mwea Region, Kenya African
Journal of Agricultural Research, 13(8): 379-388.
Nguetti, J. H., Imungi, J. K., Okoth, M. W., Wang’ombe, J., Mbacham, W. F.
and Mitema, S. E. (2019). Consumers’ awareness of the presence of
pathogenic bacteria and pesticide residues on tomatoes sold in Nairobi.
African Journal of Agricultural Research, 14(35): 2146-2158.
Nguetti, J. H. (2019). Pesticide residues and microbial contamination of
tomatoes produced and consumed in Kenya. Doctor of Philosophy in
Food and Quality. University of Nairobi.
Niassy, S., Maniania1, N. K., Subramanian1, S., Gitonga, L. M., Mburu, D. M.,
Masiga, D. and Ekesi, S. (2012). Selection of promising fungal
biological control agent of the western flower thrips Frankliniella
occidentalis (Pergande). Letters in Applied Microbiology, 54: 487–493.
93
Njogu, P., Mutuku, M. and G. Nyagah. (2013). Assessment of the Current
Patterns and Practices of use of Pesticides in Tomato Based Agro
system in Kaliluni, Kathiani Constituency, Kenya. International Journal
of Soil, Plant and Environmental Science, 1(1): 10-15.
Njoroge, H.W. (2014). Management of Root Knot nematode and Fusarium wilt
of tomato by pre-treatment of seedlings with chemicals and biological
agents. MSc. Thesis. University of Nairobi.
NouriAiin, M., Askary, H. and Zare, R. (2014). Isolation and Characterization
of Entomopathogenic Fungi from Hibernating Sites of Sunn Pest
(Eurygaster integriceps) on Ilam Mountains, Iran. International Journal
of Current Microbiology and Applied Sciences, 3: 314-325.
Nyasani, J. O., Meyhofer, R., Subramanian, S. and Poehling, H. M. (2013).
Seasonal abundance of Frankliniella occidentalis and its natural
enemies in different French bean agro-ecosystems in Kenya. Journal of
Pest Science, 86: 515–523.
Nyasani, J. O., Sevgan, S., Hans-Michael, P., Nguya, K. M.
Sunday, E. and Rainer, M. (2015). Optimizing Western Flower Thrips
Management on French Beans by Combined Use of Beneficials and
Imidacloprid. Journal of Applied Entomology, 6: 279-296.
Ochilo, N. W., Gideon, N., Nyamasyo, D. K., Washington, O., Miriam, O.,
Florence, C., Teresia, K. and Eunice, K. L. (2018). Characteristics and
production constraints of smallholder tomato production in Kenya.
Scientific African. doi: https://doi.org/10.1016/j.sciaf.2018.e00014.
94
Omondi, V. J. (2015). Effects of insecticide treated nets in the management of
tomato pests and their impact on natural enemies and yield in Nairobi
and Murang’a Counties. MSc. Thesis. Kenyatta University, Kenya.
Omukoko, C. A., Turoop, L. and Wekesa, V. W. (2017). Laboratory
assessment of red spider mites Tetranychus evansi damage on tomato
plants enhanced with Beauveria bassiana. African Journal of
Horticulture and Science, 12: 8-15.
Onduso, J. N. (2014). Management of bacterial wilt of tomato by use of
resistant Rootstock. MSc. Thesis. University of Nairobi, Kenya.
Ongwae, L. M. (2016). Analysis of factors influencing tomato farmers’
willingness to adopt innovative timing approaches for management of
climate change effects in Taita Taveta County, Kenya. MSc. Thesis.
University of Nairobi, Kenya.
Ortiz-Urquiza, A. and Keyhani, N. O. (2013). Action on the Surface:
Entomopathogenic Fungi versus the Insect Cuticle. Insects, 4(3): 357-
74.
Ouma, B., Muthomi, J. and Toroitich, F. (2014). Management of thrips in
French beans by integrating biological and synthetic pesticides in
conventional spray regimes. Journal of Renewable Agriculture, 2(2):
27-37.
Paramasivam, M. and Selvi, C. (2017). Laboratory bioassay methods to assess
the insecticide toxicity against insect pests. Journal of Entomology and
Zoology Studies, 5(3): 1441-1445.
95
Payal, S., Seema, T. and Radhika, N. (2019). Recent Advances in Breeding of
Tomato-A Review. International Journal of Current Microbiology and
Applied Sciences, 8(3): 1275-1283.
Pucheta, D. M., Macias, A. F. and Navarro, S. R. (2016). Mechanism of Action
of Entomopathogenic Fungi. In Interciencia, 156(12): 2164-2171.
Ramathani, I., Semalulu, O., Ddamulira, G. and Hongsik, S. (2018). Efficacy
of Conventional, immune-botanical and Egg Yolk mixture on the
management of Diseases and insect pests of tomato Solanum
lycopersicum L. in Uganda. Advances in Crop Science Technology,
6(4): 388-413.
Rashidi, F. and Ganbalani, G. N. (2018). Toxicity and Sublethal Effects of
Selected Insecticides on Life Parameters of Encarsia formosa
(Hymenoptera: Aphelinidae), a Parasitoid of Trialeurodes
vaporariorum (Hemiptera: Aleyrodidae). Journal of Entomological
Science, 53(4): 543-553.
Reitz, S. R. (2009). Biology and ecology of the western flower thrips
(Thysanoptera: Thripidae): The making of a pest. Florida Entomology,
92: 7–13.
Rioux, C., Jordan, D. C. and Rattrap, J. B. M. (2014). Calorimetric
determination of catechu siderophores in microbial cultures. Journal of
Microbiology, 133: 909-913.
Route to Food Initiative (RTFI). (2019). Pesticides in Kenya: Why our health,
environment and food security are at stake, 1: 1-34.
96
Sabbour, M. M. (2014). Biocontrol of the tomato leaf miner (Tuta absoluta)
(Meyrick) (Lepidoptera: Gelechiidae) in Egypt. Journal of Crop
Protection, 3(3): 499-503.
Samota, R. G., Jat, B. L. and Mamta, D. C. (2017). Efficacy of newer
insecticides and biopesticides against thrips, Scirtothrips dorsalis Hood
in chilli. Journal of Pharmacognosy and Phytochemistry, 6(4): 1458-
1462.
Sandhu, S. S., Sharma, A. K. and Malhotra, S. (2012). Myco-biocontrol of
insect pests: Factors involved, mechanism and regulation. Journal of
Pathogens, 1: 1-10.
SAS Institute. (2013). Base SAS 9.4 procedures guide: Statistical procedures,
40.
Sawant, I. S. (2014). Trichoderma- foliar pathogen interactions. Mycology
Journal, 8: 58-70.
Semeao, A. A., Martins, J. C., Picanco, M. C., Bruckner, C. H., Bacci, L.,
Rosado, J. F. (2012). Life tables for the quava psyllid Triozoida limbata
in Southern Brazil. Biological control, 57: 779-788.
Shafie, H. A. F. and Abdelraheem, B. A. (2012). Field evaluation of three
biopesticides for integrated management of major pests of tomato,
Solanum lycopersicum L. in Sudan. Agriculture and Biology Journal of
North America, 3(9): 340-344.
97
Shailendra, S., Awathi, A. K., Tomar, R. K. S., Verma, S. K. and Chaure, N. K.
(2018). Seasonal Incidence of Serpentine Leaf Miner (Liriomyza trifolii
Burgess) on tomato at Bilaspur District of Chhattisgarh. Trends in
Biosciences, 11(1): 28-30.
Sharma, H. C., War, A. R. and Sahrawat, K. L. (2012). Botanical Pesticides:
Environmental impact safety of Biotechnology and conventional
integrated pest management technologies, Studium Press LLC, Texas,
159-190.
Sharma, A., Neupane, K. R., Regmi, R. and Neupane, R. C. (2018). Effect of
intercropping on the incidence of Jassid (Amrasca biguttula Ish.) and
Whitefly (Bemesia tabaci Guen.) in Okra (Abelmoschus esculentus L.
Moench) in Kaski, Nepal. Journal of Agriculture and Natural
Resources, 1(1): 179-188.
Shobha, G. and Kumudini, B. S. (2012). Antagonistic effect of the newly
isolated Bacillus sp. on Fusarium oxysporum. International Journal of
Applied Science, 1(3): 463:474.
Sigei, G. K., Hillary, N. K., Antony, K. M., Mariam, M. and Mary, M. C.
(2014). Challenges and Strategies to Improve Tomato Competitiveness
along the Tomato Value Chain in Kenya. International Journal of
Business and Management, 9: 9-15.
Silva, G. A., Pereira, R. M., Rodrigues-Silva, N., Souza, T. C., Ferreira, D. O.,
Queiroz, E. A., Silva, G. A. R. and Pican o, M. C. (2017). Wax
Removal and Diamondback Moth Performance in Collards Cultivars.
Neotropical Entomology, 46(5): 571-577.
98
Singh, S., Singh, D. R., Kumar, K. and Birah, A. (2014). Eco-friendly
management modules for bacterial wilt (Ralstonia solanacearum) of
tomato for protected cultivation in a tropical island ecosystem.
Biological Agriculture and Horticulture, 30(4): 219-227.
Sivakalai, S. and Ramanathan, N. (2015). Simple and cost effective method for
mass production of entomopathogenic fungi by using naturally
available substrate. International Journal of Frontiers in Science and
Technology, 2(4): 67-77.
Sola, P., Mvumi, B. M., Ogendo, J. O., Mponda, O., Kamanula, J. F., Miranda,
S. P., Belmain, S. R. and Stevenson, P. C. (2014). Botanical pesticide
production, trade and regulatory mechanisms in sub-Saharan Africa:
making a case for plant-based pesticidal products. Food Security, 6(3):
369–384.
SPSS Institute. (2012). Doing data analysis with SPSS: Version 18. Australia:
Brooks/Cole Cengage Learning.
Srijita, D. (2015). Biopesticides: an eco-friendly approach for pest control.
World Journal of Pharmacy and Pharmaceutical Sciences, 4(6): 250-
265.
Ssemwogerere, C., Ochwo-Ssemakula, M. K. N., Kovach, J., Kyamanywa, S.
and Karungi, J. (2013). Species composition and occurrence of thrips
on tomato and pepper as influenced by farmers’ management practices
in Uganda. Journal of Plant Protection Research, 53(2): 158-164.
Starnes, R. L., Liu, C. L. and Marrone, P. G. (2013). History, use and future of
microbial insecticides. Journal of Entomology, 6: 83:91.
99
Stuart, R. R., Yulin, G. and Zhongren, L. (2016). Insecticide Use and the
Ecology of Invasive Liriomyza Leafminer Management. Journal of
Economic Entomology, 8: 234-257.
Sudeepa, K. J. and Manoj, K. (2017). Effect of weather parameters on
incidence of whitefly Bemisia tabaci (Gennadius) on tomato. Journal of
Entomology and Zoology Studies, 5(6): 304-306.
Sumitra, A., Kanojia, A. K., Kumar, A., Mogha, N. and Sahu, V. (2012).
Biopesticide formulation to control tomato lepidopteran pest menace.
Current Science, 102(7): 1051-1057.
Surendra, K. D. (2017). Managing Western Flower Thrips (Thysanoptera:
Thripidae) on Lettuce and Green Peach Aphid and Cabbage Aphid
(Hemiptera: Aphididae) on Broccoli with Chemical Insecticides and the
Entomopathogenic Fungus Beauveria bassiana (Hypocreales:
Clavicipitaceae). The Open Plant Science Journal, 10: 21-28.
Szostek, S. A., Priscila, R. and Jasmin, S. (2017). Western flower thrips can
transmit Tomato spotted wilt virus from Virus-infected tomato fruits.
Plant Health Progress, 18: 1-6.
Tarla, D. N., Manu, I. N., Tamedjouong, Z. T., Kamga, A. and Fontem, D. A.
(2015). Plight of Pesticide Applicators in Cameroon: Case of Tomato
Lycopersicon esculentum Mill. Farmers in Foumbot. Journal of
Agriculture and Environmental Science, 4(2): 87-98.
Tinyami, E. T., Choi, J. W., Tumenta, T. S., Eko, A. and Chick, O. A. (2014).
Small-Scale tomato cultivators’ perception on pesticides usage and
practices in Buea Cameroon. Health, 6: 2945-2958.
100
Toroitich, F., Knapp, M., Nderitu, J., Olubayo, F. and Obonyo, M. (2014).
Susceptibility of geographically isolated populations of the tomato red
spider mite Tetranychus evansi Baker to commonly used acaricides on
tomato crops in Kenya. Journal of Entomological and Acarological
Research, 46(1): 18-25.
URT. (2014). What is the Literacy Rate in United Republic of Tanzania, a
Country in the Continent of Africa? [http://country- acts .findthedata.
org/ q/ 188/2395/What-isthe-literacy-rate-in-Tanzania-United-
Republic-Of-a-country-in-the-continent-of-Africa].
Usman, J. and Bakari, U. M. (2013). Profitability of Dry Season Tomato
Lycopersicon esculentum Mill. Production in Fufore Local Government
Area of Adamawa State Nigeria. International Journal of Engineering
and Science, 2(11): 113-117.
Viuda-Martos, M., Sanchez-Zapata, E., Sayas-Barbera, E., Sendra, E., Perez-
Alvarez, J. A. and Fernandez-Lopez, J. (2014). Tomato and tomato by-
products. Human health benefits of lycopene and its application to Meat
Products: A Review. Critical Reviews in Food Science and Nutrition,
54(8): 1032-1049.
Wachira, J., Mshenga, P. and Saidi, M. (2014). Comparison of Profitability of
Small scale Green house and Open field Tomato Production Systems in
Nakuru-North District, Kenya. Asian Journal of Agricultural Sciences,
6(2): 54-61.
101
Wagnitz, J. J. (2014). Biopesticides use in IPM for low desert vegetable and
fruit production, Paper AA13618603, Degree of Doctor of Plant Health.
College of Agricultural Sciences and Natural Resources, ETD
Collection for University of Nebraska, Lincoln.
Wakil, W., Brust, G. E. and Perring, T. (2018). Sustainable management of
arthropod pests of tomato. Journal of Plant Proctection Research, 350-
372.
Wanjohi1, J. W., Geoffrey, O. W. and Charles M. M. (2018). Integrated
Management of Fusarium Wilt-Root Knot Nematode Complex on
Tomato in Central Highlands of Kenya. Sustainable Agriculture
Research, 7(2): 8-18.
Watanabe, T. (2010). Pictorial atlas of soil and seed fungi: morphologies of
cultured fungi and key to species. Third edition. Taylor and Francis
Group, LLC.
Wright, H J., Ochilo, W., Pearson, A., Finegold, C., Oronje, M., Wanjohi, J.,
Kamau, R., Holmes, T. and Rumsey, A. (2016). Using ICT to
strengthen agricultural extension systems for plant health. Journal of
Agricultural and Food Information, 17(1): 23-36.
Wu, S., Ago, Y., Zhang, Y., Wang, E. and Xu, X. (2014). An
Entomopathogenic Strain of Beauveria bassiana against Frankliniella
occidentalis with no Detrimental Effect on the Predatory Mite
Neoseiulus barkeri? Evidence from Laboratory Bioassay and Scanning
Electron Microscopic Observation. PLoS ONE, 9(1): 84-95.
102
Youssef, A. N. (2015). Efficacy of the entomopathogenic nematodes and fungi
for controlling the tomato leaf miner, Tuta absoluta (Meyrick)
(Lepidoptera: Gelechiidae). Arab Universal Journal of Agricultural
Science, 23(2): 591–598.
Zekeya, N., Chacha, M., Ndakidemi, P. A., Materu, C., Chidege, M. and
Mbega, E. R. (2017). Tomato leaf miner Tuta absoluta Meyrick: A
threat to tomato production in Africa. Journal of Agriculture and
Ecology Research, 10(1): 1-10.
103
APPENDICES
Appendix I: Survey questionnaire
A field survey on economically important arthropod pests on tomatoes and their management by growers in Bungoma County, Kenya. Questionnaire No: ………. Date of data collection: ……… A. Details of respondent Name of farmer: …… Cell phone No: ……………………... Sex: 1. Male 2. Female …………………………… Marital status: 1. Married 2. Single…………….. 3. Divorced 4. Widowed………… Level of education: 1. Non …………. 2. Primary………….. 3. Secondary 4. Post-secondary….. Age group: 1. < 25 yrs. 2.26-30 yrs.…………. 3. 31-35ys 4.36-40yrs………….. 5. 41-45yrs 6. 46-50yr…………... 7. 51-55yrs 8. Over 55yrs………. Responded: 1. Owner 2.Manager…………... 3. Employee 4.Other (specify)….… Household size: ……………………………....
B. Description of the study area Sub-county: ……. Ward: ………… Location………… Village: ………. Nearest shopping centre: …… Distance to the market (Km): ….. GPS coordinates: Longitude: ………… Latitude……………... Altitude: …………….. Farm size (Acres): … Soil type: ….……..…. Agro-Ecological Zone…………………….…..
a. What is the size of your farm in hectares? 1. 0.25…...... 2. 0.5……………... 3. 1.0………………..4. 1.5……………... 5. >2.0…………….. b. For how long have you been growing tomato? 1. <1yr…………...2. 2yrs…………….. 3. 3yrs………...... 4. 4yrs…………….. 5. > 5yrs…………..
104 c Do you plan to continue producing tomatoes in future? . 1. Yes……………...2. No…………………………. If No give a reason? i) …………………………………………………………... ii) …………………………………………………………… d Which variety of tomato do you currently grow? . 1. Kilele………….2. Carl J………….3. Riogrande…………… 4. Money maker….5. Safari…………..6. Rambo……………... 7. Commando…….8. Any other (Specify) ……………. e What makes you prefer the variety that you chose? Give a reason(s) . 1. High yielding 2. Have longer shelf-life..……. 3. Early maturity……………..4.Good market quality…………. f. Where do you obtain your seedlings? 1. Own established nursery…...2. Buy seedlings...... 3. Others (specify)...... g Do you carry out irrigation or rain fed production? . 1. Irrigation 2. Rain-fed......
2.If irrigation, what is the source of irrigation water? 1. River……………..2. Borehole…………. 3. Dam………………... 3.If you carry out irrigation, state the type of irrigation method adopted; 1. Furrow…………………2. Overhead…………….. 3. Sprinkler……………….4. Drip…………..……… h What is the source of labour in your farm? . 1. Family 2.Hired 3.Both...... i. Do you use fertilizers in production? 1. Yes…………2. No………………
4.If yes, which of these; 1. DAP 2. CAN/UREA…………………… 3. NPK 4. Others (specify) ………………
C. Crop production practices
D. Details on insect pests, diseases and management practices a. What are the main insect pests you encounter in tomato? (Pictures) 1. Whiteflies...... 2. Leaf miner moth …………… 3. Aphids…………………….4. Thrips……………………….. 5. Cutworms………...... 6. Red spider mites …………… 7. African bollworm…………8. Any other (specify)…………. b Out of the pests encountered in your farm, rank three most serious in reducing yield and quality of tomato (In descending order)
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1 (a)……………………….2. (b)………………… 3 (c)……………………… c. In your own rating, what percentage of tomato yield is lost due to attack by each of the pest you have ranked above Pest a)…1. <10%.....2. 20-40%...... 3. 40-60%...... 4. 60-100%...... Pest b)…1. <10%….2. 20-40% 3. 40-60%...... 4. 60-100%...... Pest c)…1. <10%...... 2. 20-40%...... 3. 40-60%...... 4. 60-100%...... d. Which cropping season do you experience highest insect pest population 1. First season…………..2. Second season…………… Howe have you been managing insect pests and diseases to achieve production? Use of: 1. Chemicals...... 2. Tolerant variety…………. 3. Use of traps……………….4. Crop rotation…………….. 5. Combination (specify)……6.Any other (specify) ……… Iff synthetic pesticides are used in pest management, state the following: Trade name Target pest Spray Efficacy (10-20%:Slightly of the product frequency( effective,20-50%:effective, weekly, >50%:very effective fortnight, monthly)
1. 2. 3. 4.
g. At what time do you carry out insecticide sprays
1. Morning...... 2. Afternoon...... 3.Evening...... h. Where do you store the pesticides after use? 1. In farm store……………..2. In cupboard 3. Others (specify)………….... i. Do you experience the following diseases during the same period that your tomatoes are attacked by insect pests (Pictures)? 1. Bacterial wilt……………….2. Blossom end rot………… 3. Fusarium wilt………………4. Early blight……………… 5. Multiple (Specify)…………. j Have you ever heard about biological control strategies as . an alternative to synthetic pesticides? 1. Yes………………………2. No……………………. k If yes, from whom did you obtain the information? 1. Training...... 2. Agricultural extension officer……. 3. Radio/Tv………4. Internet……………………………. Dol you have access to credit facilities?
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1. Yes…………...2. No……………… If yes, from which institution? 1. Bank…………2. Agricultural Cooperatives……… 3. Others (specify)…………………………………….. m. Where do you get advice on the usage of pesticides in pest management? 1. Agricultural extension staff…….....2. Agrovet………….. 3. Agricultural trainings……………...4. Neighbour……….. 5. Agricultural Radio/TV show………6. Internet………….. n Are there agricultural extension services in your (ward, village)? 1. Yes…………………………..No…………………… o If a better method of managing insect pests is proposed by this study, would you be ready to use it? 1. Yes……………..2. No………………….
E. Harvest and Post-harvest handling practices a. How do you dispose the crop residues after harvest? 1. Left unattended in the farm….2. Buried……………… 3. Collected and burnt…………..4. Feed to livestock…... 5. Used as manure………………... b. What is the average yield per season in crates (1 crate 60kg) 1.>5……………………..2. 5-10………………………... 3. 11-15…………………4. 15-20………………………. 5. >20………………….. c. Do you sell the tomato harvest? 1. Yes……………………….2. No………………………….
If yes, where do sell your produce? 1. Direct market………………..2. Brokers………………….. 3. Cooperatives………………...4. Others (specify)…………. c. Which other problems do you encounter in tomato production? 1. Poor road transport…………..2. Price fluctuation………… 3. Interference with brokers……4. Others (specify)………….
Thank you for your attention
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Appendix II: Photo-cards of arthropod pests and disease symptoms of tomato.
Plate 1: Western flower thrip Plate 2: Aphid
Plate 3: Whitefly Plate 4: Leaf miner moth
Plate 5: Bacterial wilt disease Plate 6: Blight on leaves
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Appendix III: Introductory letter for survey
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Appendix IV: Research authorization
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Appendix V: Weather data for Bungoma County during the field trials in 2018
Temperature (0C)
Month Maximum Minimum Average Rainfall (mm)
January 30.4 14.5 22.4 58
February 30.9 15.0 23.0 64
March 30.4 15.4 22.9 124
April 28.9 16.0 22.4 210
May 27.8 15.8 21.8 209
June 27.3 15.2 21.2 120
July 27.1 15.0 21.1 103
August 27.3 14.8 21.1 126
September 27.8 14.6 21.2 131
October 26.0 15.1 20.6 157
November 25.9 15.1 20.1 139
December 29.6 14.9 22.2 70
Source:https//www.worldweatheronline.com/bungomaweather/averages/wester
n/ke.aspx/Accessed on 03/01/2019.
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