In Vitro Efficacy of Fungicides on Sclerotinia sclerotiorum and their Potential for Control of Stem Rot in Indian Mustard (Brassica juncea L.)

Sclerotinia stem rot or stem blight or white rot disease caused by Sclerotinia sclerotiorum (Lib.) de Bary is a serious problem in mustard crop in northern India. Efficacy of six fungicides, carbendazim 50 WP, propiconazole 25 EC, hexaconazole 5 EC, difenaconazole 25 EC, carbendazim 12%+mancozeb 63% 75WP and penconazole 10 EC were tested against S. sclerotiorum. Under in vitro studies, fungicides carbendazim 50 WP and carbendazim 12%+mancozeb 63% mixture 75 WP at 0.1% concentration completely inhibited the mycelial growth, sclerotial formation and germination of sclerotia. Propiconazole 25 EC, hexaconazole 5 EC, difenaconazole 25 EC, penconazole 10 EC were also found effective at higher concentration (0.05% and 0.1%) but at lower concentrations (less than 0.05%), these fungicides were observed less effective to inhibit the mycelial growth, sclerotial formation and germination of sclerotia. In field experiments during rabi 2007–08 and 2008–09, seed treatment with carbendazim 50 WP @ 2 g kg⁻¹ and two foliar sprays of same at 0.1% was most effective for disease control and increased seed yield in both the years. In this treatment lowest disease incidence (9.32%), minimum disease intensity (7.50%), highest disease control (76.92%), maximum average production (14.89 q ha⁻¹) and maximum net profit as well as benefit-cost ratio (2.01:1) was recorded. Seed treatment with carbendazim 50 WP @ 2 g kg⁻¹ and two foliar sprays of carbendazim 12%+mancozeb 63% 75 WP at 0.2% was also found effective in disease control (59.18%) and increased seed yield (12.96 q ha⁻¹) over untreated control.