Bioefficacy of certain chemical insecticides against rice yellow stem borer (Scirpophaga incertulas Wlk.)

Abstract

Rice is the major staple food in Jharkhand in India and is threatened by various biotic and abiotic stresses. Among the insect pests that imperil the rice cultivation in Jharkhand, the yellow stem borer (Scirpophaga incertulas Wlk.) is one of the most notori-ous ones. The present investigation was conducted in Kharif 2018 to study the bioefficacy of certain chemical insecticidal treatments against yellow stem borers in rice measured in terms of mean values of dead heart (% DH) and white ear (%WE). Ten insecticidal treatments, namely, T1-Flubendiamide 240 SC + Thiacloprid 240 SC (combination product) @ 200 ml/ha, T2-Flubendiamide 240 SC + Thiacloprid 240 SC (combination product) @ 250 ml/ha, T3-Imidacloprid 17.8 SL @150 ml/ha, T4-Flubendiamide 480 SC @ 50 ml/ha, T5-Rynaxypyr 20 SC @150 ml/ha, T6-Fipronil 80 WG @ 65 g/ha, T7-Dinotefuran 20 SG @ 200 g/ha, T8-Fipronil 0.3 GR followed by Chlorpyriphos 20 EC @2000 ml/ha, T9-Chlorpyriphos 20 EC@ 2000 ml/ha and T10-untreated control were taken for the experiment. The results showed that two of the insecticidal treatments,namely T2-flubendiamide 240 SC + thiacloprid 240 SC @ 250 ml/ha (2.07% DH and 2.30% WE) and T4-flubendiamide 480 SC @ 50 ml/ ha (1.89% DH and 2.49% WE), were at par with each other. They performed better than all the other treatments, suggesting that using these two newer insecticidal treatments could provide all-around protection for the rice crop against rice yellow stem borer in terms of both dead heart and white ear.