Bioefficacy of Different Formulations of Chlorantraniliprole 0.53%+Fipronil 0.8% GR Against Yellow Stem Borer of Rice

The study was conducted during rabi (December, 2020–May, 2021), and kharif  (July–December, 2021) at University Instructional Farm, UBKV, Pundibari, Cooch Behar, West Bengal, India with a new combination of insecticides Chlorantraniliprole 0.53% w/w and Fipronil 0.8% w/w GR with different formulations to evaluate the bio-efficacy of these combinations of insecticides against yellow stem borer (Scirpophaga incertulas). In this study three formulations of Chlorantraniliprole 0.53% w/w+Fipronil 0.8% w/w GR @ 5.63 kg ha-1, @ 7.50 kg ha-1 and @ 9.38 kg ha-1 were used and Chlorantraniliprole 0.40% GR @ 1 kg ha-1, Fipronil 0.3% GR @ 25 kg ha-1, Cartap hydrochloride 4% GR @ 18.75 kg ha-1  and untreated control were evaluated against yellow stem borer in rice crop. The result suggested from the present investigation that Chlorantraniliprole 0.53%+Fipronil 0.8% GR @ 7.50–9.38 kg ha-1 was found best and effective as well as at par with each other against rice yellow stem borer. It has been observed that Chlorantraniliprole 0.53%+Fipronil 0.8% GR  @ 9.38 kg ha-1 registered good yield, 4.81 t ha-1 and 4.72 t ha-1 which were on par with Chlorantraniliprole 0.53%+Fipronil 0.8% GR @ 7.50 kg ha-1 i.e., 4.79 t ha-1 and 4.70 t ha-1 in two consecutive seasons i.e., rabi, 2020–21 and kharif, 2021 respectively Whereas, Chlorantraniliprole 0.53%+Fipronil 0.8% GR @ 7.50 kg ha-1 found much suitable with effective, safe and favorable cost-benefit ratio. The study also showed that there was no significant difference in density of predators in treated and untreated plots.