Field evaluation of biopesticides against rice insect pests under organic farming

Abstract

Neem based commercial formulations Ecotin (azadirachtin 5%; 50,000 ppm) @ 150,175 and 200 ml ha-1, and standard checks- Achook (azadirachtin 0.15%; 1500 ppm) @ 2500 ml ha-1 were applied at pest appearance for evaluating them for the management of rice stem borers Scirpophaga spp. and leaf folder Cnaphalocrocis medinalis (Guenee) on basmati and non-basmati rice under organic cultivation conditions. In basmati, the reduction of deadhearts due to stem borers was observed to be maximum with Ecotin @ 200 ml ha-1 as 55.79 and 56.84% at 5 and 10 DAS, respectively; while white ears were at 55.99% in 2019; and reduction of deadhearts was 50.45 and 45.75% at 5 and 10 DAS, respectively, while white ears reduced up to 50.71% in 2020. Similarly, reduction of damaged leaves due to leaf folder was 55.80 and 59.62% at 5 and 10 DAS, respectively; and in 2020, it was 50.45 and 45.75% at 5 and 10 DAS, respectively. Ecotin 5% @ 200 ml ha-1 gave maximum crop yield (31.29 q ha-1). In non-basmati rice too the reduction of deadhearts was maximum with Ecotin @ 200 ml ha-1, while white ears reduced by 50.47% in 2019, with similar trend in 2020; also results were of similar trend with leaf folder. The occurrence of spiders revealed a non-significant difference among the treatments. The biopesticides caused no residual or phytotoxic effects and were safe to the environment and predatory fauna.