Chemical management of powdery mildew caused by Erysiphe polygoni DC on Urdbean and its economic analysis

Powdery mildew of Urdbean caused by Erysiphe polygoni DC is one of the major constraints in the production, which cause both qualitative and quantitative loss of grains. In the present study we have evaluated the efficacy of fungicides for managing powdery mildew of urdbean. The fungicides Penconazole 10% EC (@ 0.25 ml/ L, 0.5 ml/L, 1.0 ml/ L and 1.50 ml/ L), Hexaconazole 5% SC @ 1.0 ml/ L, Difenoconazole25% EC@ 0.50 ml/L and Captan 70% + Hexaconazole 5% WP @ 1.25 g /L were evaluated for their bio-efficacy against powdery mildew of Urdbean. Pooled data of experiments conducted at MARS, UAS, Dharwad for two years during 2017 and 2018 revealed that, all the chemicals were found effective in reducing the severity of the disease and their by increasing the urdbean yield. Among them, Penconazole 10% EC @ 1.5 ml/L was found to be the most effective in managing the powdery mildew of urdbean (9.91 PDI) and which is on par with Penconazole 10% EC @ 1.0 ml/L recorded powdery mildew severity of 10.15 PDI. Penconazole 10% EC @ 0.50 ml/L (11.93 PDI) was the next best treatment followed by Difenconazole 25% EC@ 0.50 ml/ L (13.25 PDI) and Hexaconazole 5% SC @ ml/L (13.54 PDI) when compared to untreated control which has recorded the maximum PDI of 66.90. Significantly the highest seed yield of 686.20 kg/ha was observed with Penconazole 10% EC @ 1.5 ml/L with B:C ratio of 2.20 followed by Penconazole 10% EC @ 1.0 ml/L (683.00 kg/ha) with maximum B: C ratio of 2.22 compared to least seed yield of 308.83 kg/ha in untreated control with least B:C of 1.06. Thus the dose of Penconazole10% EC @ 1 ml per liter of water was found to be the minimum dose required for better management of the powdery mildew disease in urdbean.