Location, Survival, Transmission and Control of Seedborne, Macrophomina phaseolina Causing Dry Root Rot and Leaf Blight in Urdbean

Dry root rot and leaf blight of urdbean caused by Macrophomina phaseolina [=Rhizoctonia bataticola] is an important seed and soil-borne disease of India. Seeds of urdbean vars. PDU-1, IPU 981, IPU 94-2, IPU-982, Pant U-30, KU-82-29, T-9 and Pant U-19 carried 2 to 12% infection of M. phaseolina with maximum being in var. Pant U-19, Varieties IPU 96–12, PLU-241, PLU-137, KU-311 and KU-315 did not carry the fungal infection. The pathogen was invariably present in the seed coat of all the infected seeds and in the cotyledons of 35% infected seeds. The pathogen survived in infective state upto twenty months in seeds and was transmitted from to seedlings by local contact in the ratio of 1: 0.25 (seed infection: seed transmission). Seed treatment with topsin M (1.0 g/kg. seed), bavistin 50 WP, indofil M-45 and jkstein (each 2.0 g/kg. seed) eliminated the fungus from the infected seeds.