Biocontrol of Clerotium rolfsii Sacc. Causing Collar Rot of Brinjal

Abstract

Out of 54 isolates of fungi and bacteria isolated from soil, three isolates of Trichoderma harzianum Rifai (Th-l, Th-2 and Th- 3), two of T. viride Pers. for (Tv-l and Tv-2) and one each of Penicillium sp., P.cyelopium Westling, Eupenicillium sp., Aspergillus sp., A. flavus Link., A.fumigatus Fres., A.niger Van Tieghem and an unidentified bacterium were found antagonistic to Sclerotium rolfsii Sacco All the isolates of T.harzianum, T. viride and Gliocladium sp. were found to be potential antagonists when tested by dual culture technique and culture filtrate methods. Microscopic observations revealed the mycoparasitic activity of T.harzianum in dual culture. Inhibitory activity of autoclaved culture filtrate was less effective as compared to filter-sterilized culture filtrate. Culture filtrate of T.harzianum (Th-2)and Gliocladium sp. were the most effective in inhibiting sclerotial germination. Complete inhibition of sclerotial germination was observed in T.harzianum (Th-l, Th-2 and Th-3), T. viride (Tv-l and Tv-2) and Glioeladium sp. treated sclerotia after 30 days of incubation in soil. Wheat bran substrate supported maximum growth of T.harzianum and T. viride. MiXing of wheat bran culture of T.harzianum (Th-2), T.viride (Tv-2) and Glioeladiu, sp. @ 10 glkg soil reduced the seedling mortality to 12.71, 14.72 and 17.98 per cent, respectively as compared to 86 per cent in check under green house conditions.