Efficacy and economics of promising granular insecticides against yellow stem borer on semi-deep water rice

The treatments included 3 dosages each of 4 granular insecticides, viz., chlorpyriphos 10 G @ 0.75, 1.0 & 1.25 kg a.i. ha⁻¹; cartap 4 G @ 0.6, 0.8 & 1.0 kg a.i. ha⁻¹; and fipronil 0.4 G @ 0.05, 0.075 & 0.1 kg a.i. ha⁻¹, a standard insecticide carbofuran 3 G @ 1.0 kg a.i. ha⁻¹ besides untreated control. The results indicated that cartap 4 G @ 0.6 kg a.i. ha⁻¹ followed by chlorpyriphos 10 g @ 1.25 kg a.i. ha⁻¹, fipronil 0.4 G @ 0.075 kg a.i. ha⁻¹ and chlorpyriphos 10 G @ 0.75 kg a.i. ha⁻¹ were most effective with average yellow stem borer infestation of 2.9, 3.4, 3.4 and 3.4%, respectively, in comparison to 8.1% infestation in untreated control. The yield data revealed that fipronil 0.4 G @ 0.075 kg a.i. ha⁻¹ followed by carbofuran 3 G @ 1.0 kg a.i. ha⁻¹, chlorpyriphos 10 G @ 0.75 kg a.i. ha⁻¹ and cartap 4 G @ 0.8 kg a.i. ha⁻¹ were most effective with average production of 24.39, 22.38, 22.20 and 22.13 q ha⁻¹, in comparison to 15.70 q ha⁻¹ in untreated control. The economic analysis of different insecticidal treatments indicated that chlorpyriphos 10 G @ 0.75 kg a.i. ha⁻¹ with average MBCR of 4.07 was most effective and economically profitable against yellow stem borer. It was followed by cartap 4 G @ 0.6 kg a.i. ha⁻¹ and chlorpyriphos 10 G @ 1.0 kg a.i. ha⁻¹ with average MBCR of 2.33 and 2.26, respectively.