Potential strain of trichoderma spp. to control damping off of disease in chilli.

The present investigation deals with the population of soil fungi in chilli field of Thiruvarur District. The antibiotic ability and potential strain of Trichoderma spp.isolated from chilli field soil were used against damping off disease and its tolerance to antibiotics. Among the soil fungi, tested Trichoderma spp. showed maximum activity in controlling the disease with influence of soil physico-chemical parameters. The antibiotic interactions of some soil fungi against Pythium debaryanum were studied in vitro dual culture experiments. All the Trichoderma spp. Showed the ability to inhibit the pathogen, some of the species showed variability in the percentage of inhibition were studied.

Biological control of banana wilt caused by fusarium solani (Mart.) Sacc.

The population dynamics of fungi in banana field soil, antibiotic potentiality of the soil fungi and antifungal ability of some plant extracts against Fusarium solani was studied. Maximum number of colonies were isolated during the month of November. The genus Aspergillus, Pencillium, Trichoderma, and Fusarium were isolated most frequently. Antibiotic interaction of the soil fungi against F.solani was performed. The test pathogen varied in its sensitivity to the metabolic growth products of antagonistic fungi. The maximum percentage of inhibition of pathogen was 85% against T.viride and 75% of inhibition was against A.niger. Culture filtrate of the soil fungi and the suppression of F.solani was observed. The maximum percentage of suppression of pathogen was observed against T.viride and A.niger at 20 per cent concentration level. The leaves of medicinal plant extract such as Adathoda vasica, Azadirachta indica and Vitex negundo was more effective at 20% concentration against the pathogen was reported. The leaf extracts (Adathoda vasica, Azadirachta indica and Vitex negundo) with culture filtrate of Trichoderma viride in combination of 1:1 ratio was more effective at 20 per cent level against the F.solani. However, the combined treatment of A.vasica and T.viride was more effective in controlling the pathogen F.solani causing wilt disease of banana.