EVALUATION OF RESIDENT Trichoderma isolates AGAINST Sclerotium rolfsii CAUSING DAMPING OFF OF MUNG BEAN SEEDLINGS

Abstract

An investigation was carried out to find out the most effective native Trichoderma isolate against Sclerotium rolfsii causing damping off disease of mung bean seedlings. The experiments were carried out at Mycology Laboratory and Net house of Plant Pathology Department, Sher-e-Bangla Agricultural University, Dhaka, during June 2019 - July 2020. All together 13 Trichoderma isolates collected from seven different districts in Bangladesh were explored in the investigation. The isolate JaGot.T was found to be promising in respect of mycelial growth, sporulation and antagonistic effect on Sclerotium rolfsii. The isolate JaGot.T was recorded as the fastest growing antagonistic fungus that covered 89.33 mm of the culture plate by 3 days. The 2 nd highest (86.00mm) and the 3 rd highest (85.333mm) mycelial growth rate was recorded in case of isolate GaJoy.T and GaJoy.T, respectively. The isolate JaGot.T and GaJoy.B were found to sporulate within 2 days producing 6.8433×10 4 and 6.0767×10 4 spores/mm 2 , respectively. JaGot.T inhibited 50.35% growth of S. rolfsii followed by CuDeb.B (44.17%) and GaJoy.B (44.05 %) in dual culture method. The resident Trichoderma isolate JaGot.T showed better performance against Sclerotium rolfsii causing damping off of mung bean next to Autostin and formulated Trichoderma based biopesticide ‘Bioderma’. JaGot.T yielded 76.66% seedling emergence which was statistically similar to ‘Bioderma’ (76.66%) and Autostin (78.0%). The lowest pre-emergence damping off (1.34%) and post-emergence damping off (5.367%) were recorded in case of resident Trichoderma isolate JaGot.T. The Trichoderma isolate JaGot.T also showed better performance in increasing dry matter, shoot length, root length and seedling vigor index of mung bean. The highest seedling vigor index was recorded in case of isolate JaGot.T (2336.88) which was statistically similar to Autostin and Bioderma. The isolate JaGot.T was noted as the best resident isolate of Trichoderma against Sclerotium rolfsii causing damping off of mung bean seedlings among the isolates tested.