Seed treatment and foliar application of fungicides for the management of sunflower leaf blight

Field experiments were carried out during Kharif seasons of 2008 to 2010 at Indian Institute of Oilseeds Research, Hyderabad, India for the management of sunflower leaf blight caused by Alternariaster helianthi (Hansf.) Tubaki and Nishihara. Different fungicides, viz., iprodione, carbendazim, iprodione + carbendazim, mancozeb, propiconazole and difenoconazole were evaluated in different combinations as seed treatment and foliar sprays. Seed treatment with iprodione +carbendazim 2g kg-1followed by two sprays of propiconazole 0.1% at 15 days interval recorded low leaf blight (27.9%) and higher seed yield of 975kg/ha. Seed treatment with iprodione + carbendazim 2g kg-1followed by two sprays of difenoconazole 0.1% at fortnightly interval also recorded leaf blight severity of 32.9% with seed yield of 878 kg/ha during three years of testing. However, seed treatment with iprodione 2g kg-1seed recorded high incremental benefit-to-cost ratio (8.88) followed by seed treatment with carbendazim 1g kg-1(8.43) and iprodione + carbendazim 2g kg-1seed (7.18). For the management of leaf blight of sunflower seed treatment with iprodione + carbendazim followed by two sprays of propiconazole was effective in terms of reduction of disease severity and increasing the seed yield, however, seed treatment with iprodione as well as with carbendazim was an effective treatment in terms of incremental benefit-to-cost-ratio.