Bioefficacy of Trichoderma Isolates Against Aspergillus Niger Van Tieghem Inciting Collar Rot in Groundnut (Arachis Hypogaea L.)

Antagonistic effect of 12 isolates of 3 Trichoderma strains (T. virens, T. viride, T. harzianum) against the collar rot disease-causing fungus A. niger, was studied in vitro. It was observed that T. viride 60 inhibited maximum (86.2%) growth of test fungus, followed by T. harzianum 2J (80.4%). The five varieties of groundnut grown in normal (T1), sick - A. niger infested soil (T2) and sick + Trichoderma viride 60 (seed treatment) (T3) in pot culture showed significant differences in the per cent of disease incidence of collar rot, up to 15 days after sowing (DAS). The per cent of collar rot disease incidence was higher in the GG-20 (67.4%) variety, followed by moderate in GAUG-10 and GG-13 (46%), and minimum in J-11 and GG-2 (30%) in A. niger infected pot culture, at 15 days after sowing (DAS). Based on collar rot disease incidence, groundnut varieties were screened as: susceptible, moderately susceptible and tolerant. Trichoderma seed treatment (T3) reduced 51.6% of the disease incidence in susceptible varieties and 58.1% in tolerant varieties, at 15 DAS, under A. niger infection (T2) in pot culture study.