Antagonistic effect of Trichoderma isolates against Fusarium wilt disease (Fusarium oxysporum vasinfectum) of cotton plant (Gossypium herbaceum) under in-vitro condition

Abstract

Cotton plant (Gossypium herbaceum L.) is one of the most important cash crops that is widely grown in Ethiopia. The production of cotton has been declining over the years, due to Fusarium wilt disease (Fusarium oxysporum vasinfectum). Thus, the objective of this study was to evaluate local Trichoderma isolates for their growth inhibiting potential against cotton wilt pathogen (Fusarium isolates). The antagonistic potentials of Trichoderma isolates against the test pathogen was evaluated using dual culture assays, volatile metabolite and non-volatile metabolite assays using paired plate methods. Trichoderma isolates; AUT131 (48.14%) and AUT136 (52.89%) showed the highest inhibitory effect against Fusarium wilt pathogen. Moreover, AUT131 showed the highest (78.89%) inhibitory effect against the pathogen based on dual culture assay. Use of volatile and non-volatile metabolites produced by the Trichoderma isolates also confirmed that there was a production of inhibitory substances. On the other hand, Trichoderma isolates sporulated at different pH values and the pH change was not significant (p≤0.05) except for Trichoderma isolate AUT7. This study concludes that AUT131 (48.14%) and AUT136 (52.89%) isolates have high antagonistic activity against Fusarium wilt disease of cotton plant.