In-Vitro Studies of Different Culture Media and Biocontrol Agents on Growth and Sporulation of Alternaria Alternata (Fr.) Keissler an Incitant of Broad bean (Vicia Faba L.) Leaf Blight Disease

Abstract— Studies on different culture media and biocontrol agents on growth and sporulation of Alternaria alternata (fr.) keissler causal organism of Broad bean (Vicia faba L.) leaf blight disease was conducted in vitro. Six culture media was tested for growth and sporulation of A. Alternata. It was found in that in liquid broth media, Potato dextrose broth (607 mg, dry weight of mycelium) and in solid media, maximum linear growth recorded in Potato dextrose agar (90 mm) with maximum number of spores 6.2 x 103 spores/ml. The antagonistic studies of 5 fungal biocontrol agents in dual culture technique found that all biocontrol agents statistically produced a significant antagonistic effect on linear growth and sporulation of A. Alternata. Maximum linear growth inhibition of Alternaria alternata was found in Trichoderma harzianum (17.5mm) with 89.6% inhibition and at par with Trichoderma viride (19.5mm) with 84.4% inhibition followed by T. hamatum (22.3 mm) with 74.1% inhibition and Gliocladium virens (21.0 mm) with 70.6% and minimum significant inhibition effect in T. koningii (22.8 mm) with per cent inhibition of 67.2 over the check. Highest spore inhibition of was found in T. harzianum (89.6%) and T. viride (84.4%) followed by T. hamatum (74.1%) and G. virens (70.6%) while minimum inhibition was found in T. koningii (67.25). It was further observed that T. harzianum could overgrown the growth of pathogenic fungus within 2 days and for T. viride within 3 days where as T. hamatum and G. virens took 5 days