BIOLOGICAL CONTROL OF FUNGI CAUSING POSTHARVEST ROT IN SELECTED FRUITS AND BULBS USING TRICHODERMA VIRENS

Abstract

Postharvest rot caused by fungal pathogens is a major constraint to the quality and  shelf life of Solanum lycopersicum (tomato), Cucumis sativus (cucumber), and Allium  cepa (onion). This study evaluated the in vitro antagonistic potential of Trichoderma  virens against fungal pathogens associated with postharvest rot of these crops obtained  from selected markets in Lagos State, Nigeria. Diseased samples were collected from  three markets, and associated fungi were isolated and identified based on  morphological characteristics and pathogenicity tests. The biocontrol agent was  identified using ITS sequencing. Antagonistic activity was assessed using a dual culture  assay and analysed statistically. Fungal species isolated from tomato rot were  Aspergillus niger, Fusarium oxysporum, Mucor mucedo, and Rhizopus stolonifer; from  onion rot, A. fumigatus, A. niger, Mucor mucedo, Penicillium expansum, and Rhizopus  stolonifer were isolated, while from cucumber rot, A. flavus, A. fumigatus, A. niger,  Fusarium oxysporum, Mucor mucedo, and Rhizopus stolonifer were isolated.  Trichoderma virens exhibited significant inhibitory effects against pathogens,  particularly R. stolonifer and Fusarium oxysporum, while moderate inhibition was  observed against A. niger and A. flavus. In contrast, Mucor mucedo and A. fumigatus  showed weak or no inhibition under the experimental conditions. Overall, the results  suggest that Trichoderma virens can suppress some important postharvest fungal  pathogens, although its level of activity varies among species, indicating the need for  further evaluation under in vivo and storage conditions.