Inhibitory effects of Trichoderma strains against Fusarium udum Butler causing wilt disease in pigeonpea

Trichoderma spp. has long been reported effective antagonists against a wide range of pathogens. They compete well for food and site, produce antibiotics and have an enzyme system capable of attacking a wide range of pathogens through mycoparasitism. Among these three systems of managing pathogens, antibiosis is one sucheffective tool that is employed by the Trichoderma spp. for reducing the pathogens inoculum potential. In present studies 30 Trichoderma strains isolated from different crop niches were evaluated for their potential against Fusarium udum by dual culture, effect of volatile compounds using inverse plate technique and effectiveness of non-volatile compounds through poisoned food technique. In case of dual culture all Trichoderma strains were found effective against F. udum and its growth ranged between 9.5–16.2 mm at 72 h against 29.0 mm in sole culture. Reduction in spore production ranged between 85.7–96.4% over control.In case of volatile compounds, inhibition in colony growth of the pathogen ranged between 10.3–37.8 per cent IPT nos 2,3,4,6,11,12,14,15,16,17,19,20,21,25,27,29 and 30 reduced colony growths over check. Reduction in sporulation ranged between 82.5–97.8 percent. Non-volatile compounds of Trichoderma strains caused 12.0–94.4 per cent inhibition in colony growth and 56.9–100.0 per cent reduction in sporulation over control.