Organic Management Approaches of Stem Borer in Rice Ecosystem of Assam

Abstract

Stem borer is the only insect pest which attacks the rice plant starting from tillering upto maturity stage and is of great challenge to manage due to its cryptic behavior and nocturnal habit. The experiment was laid out in the experimental field of AAU-Assam Rice Research Institute, Assam Agricultural University, Titabar both in kharif and rabi season during 2019-2022 taking three popular rice varieties of Assam, Ranjit, Ranjit Sub-1 and Gitesh. Seeds were treated with a solution of Pseudomonas florescense (10 g/liter of water /kg of seed for 12 hrs in organic and with Chlorantraniliprole 18.5 SC @ 30 g/a.i in chemical treatment and without treating the seeds in farmers’ practice plot and sown both in kharif season and rabi season. The foliar application of Beauveria bassiana (5gm/l/ha), Pseudomonas florescense (20g/l/ha) and neem product (5g/liter/ha) in organic plot and insecticide application with Chlorantraniliprole 18.5 SC @ 30 g/a.i. in the chemical plot was done at 45 days after transplanting (DAT) without application of any biopesticide or insecticide in farmers’ practice plot. The dead heart incidence drastically reduced both in chemical (6.19%) and organic treatment (7.23%) without significant difference at 65 DAT in Ranjit. The benefit cost ratio was 2.32 and 2.06 in chemical and organic approach respectively, but it was 1.78 in farmers’ practice. The use of B. bassiana, P. florescense and neem products were found to be safer to the predators as the spider and coccinellid beetle population in organic treatment (10.59 and 9.49 number/hill) was at par with farmers’ practice (12.83 and 11.67 number/hill), respectively.