Indian Journal of Weed Science

Post-emergence application of two insecticide molecules chloropyriphos 200 g/ha, fipronil 50 g/ha and three herbicide molecules chlorimuron-ethyl + metsulfuron-methyl at 4 g/ha, bispyribac-sodium at 25 g/ha, cyhalofop-butyl + penoxsulam at 135 g/ha were tested alone as well as in combination with an untreated control against grass, sedge, broad-leaf weed and stem borer for their compatibility during winter seasons 2015–16 and 2016–17. Tank mix application of cyhalofop-butyl + penoxsulam + fipronil (135 + 50 g/ha) recorded lowest incidence of dead heart (0.59%), white ear (3.53%), total weed density (8 no./m²) and weed biomass (3.5 g/m²) and enhanced weed control efficiency (84.6%), grain yield (5.23 t/ha), net returns (‘ 40.44 x 10³/ha) and benefit: cost ratio (2.02). Dead heart percentage was less (0.59 to 1.55%) in sole fipronil and its combination with different herbicide than that of chloropyriphos (0.92 to 1.92%). There was no difference in grain yield of rice in treatments, which received application of cyhalofop-butyl + penoxsulam alone and with fipronil indicating the compatibility of herbicide with insecticide.