Studies on Management of Web Blight (Rhizoctonia Solan/ Kuhn) of Mung Bean

Abstract

Mungbea [Vigna radiata (L.) Wilczek] is one ofthe most important pulse crops. It is grown in almost all parts of the country Mungbean belongs to family Leguminosae. Mung bean is an excellent source of high quality protein. Several biotic and abiotic factors influence the growth and development of Mungbean. Among them various factors, pests and diseases have a great role in declining yield of Mungbean. The major fungal diseases which infect the mungbean are web blight, (Rhizoctonia so/ani), root rot (Macrophomina phaseolina) powdery mildew (E1ysiphe polygoni), Cercospora leaf spot (Cercospora canescens)and anthracnose [Colletotrichum dematium and C. lindemuthianum].Web blight incited by Rhizoctonia so/ani Kuhn has been rated as a devastating disease of mungbean. The disease attacks all the aerial part of the plants. It caused water soaked lesions on leaves which later turn brown in colour and pathogen produced spider web like mycelium on infected leaves. In dual culture experiments Trichoderma viridae (Tv7) inhibited (60.00%) the maximum growth of the Rhizoctonia so/ani. which was significantly superior from all the tested isolates and isolate Trichoderma viridae (Tv1) was least effective to control the mycelial growth which inhibited 42.22% mycelial growth of the pathogen (Rhizoctonia so/ani). The fungicides viz. Vitavax, Prism and Melody inhibited the complete mycelial growth of Rhizoctonia so/ani at all three concentrations (1 00 ppm, 300 ppm and 500 ppm). Carbendazim was least effective over the tested fungicides which inhibited fungal growth 37.0 per cent, 44.7 per cent and 71.44 per cent at the cor:tcentrations 100 ppm, 300 ppm and ~00 ppm. Minimum disease severity was found T s (Spray of Topsin-M) 5.56% followed by T5 (seed treatment with Vitavax) 11.11% and T4 (seed treatment with Thiram) 14.81%, respectively. All treatments superior as compression to control (55.55%).