Modes of Parasitism between the Necrotrophic Fungus Botrytis cinerea and Trichoderma spp

This study aims to understand the differential antagonistic activity of the Trichoderma spp. against Botrytis cinerea (grey mould) on tomato plants. The antagonistic efficiency between Botrytis cinerea and Trichoderma spp. viz., Trichoderma reesei, Trichoderma viride, Trichoderma harzianum, Trichoderma hamatum, Trichoderma longibractum were studied in vitro using dual plate technique. The results revealed that all of the Trichoderma isolates had the ability to inhibit the mycelial growth of grey mould. The percentage reduction in the growth of B. cinerea after seven days of incubation at 23 ± 2ºC varied between 35-84%. The Trichoderma spp. such as T. reesei (A1) and T.harzianum (E1) showed the highest antagonistic activity (T. reesei (A1) – 84%; T. harzianum (E1) – 72.8%). SEM studies at cellular level have shown the collapse of hyphal wall of B. cinerea at an early stage. Clear evidence on direct parasitism was recorded on most of the Trichoderma spp. tested in this experiment. In bioassay experiments, B. cinerea applied alone was found throughout the leaf tissues in high densities after an incubation period of five days at 18°C in a moist chamber rather than when pathogen and antagonists were applied together. Based on previous records of Trichoderma spp., biocontrol potential and observations of its colonizing properties, it appears that T. reesei can compete and reduce the growth of B. cinerea in tomato plants at an early stage and enhance the growth of the plants. Keywords: Biological control, antagonistic potential, cell damage, grey mould, Trichoderma spp