In Vitro Efficacy of Native Entomopathogenic Fungi Against Western Flower Thrips Frankliniella Occidentalis (Pergande) of Tomato in Kenya

Abstract

Tomato Solanum lycopersicum L. is an important crop in Kenya. Arthropod pests are major constraints to its production and farmers rely heavily on synthetic chemicals for control, which increases costs and leads to pollution of the environment. The objective of this study was to evaluate the effectiveness of native Kenyan fungi in managing thrips as an alternative to synthetic pesticides. 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 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. Data on mortality of thrips was subjected to Analysis of Variance (ANOVA) using SAS software version 9.4 to test the effect of different treatments. Means were separated using Student Newman-Keuls test at P≤0.05. Gliocladium virens, Trichoderma virens, Fusarium solani, Fusarium oxysporum and Trichoderma afroharzianum were more virulent causing mortalities above 50%. Gliocladium virens was the most potent, causing 62.2% mortality in adults and 43.8% in nymphs at 1.0 x107 conidia ml-1. The findings showed that G. virens is a potential candidate for development as a fungal-based bio-pesticide against F. occidentalis on tomato.