Efficacy of different pesticides in suppressing yellow stem borer in spring rice (Oryza sativa) in Ratuwamai, Morang, Nepal

Abstract

Rice, a staple food for over half the global population, is crucial for food security, economic stability, and cultural significance. Its production, however, is threatened by pests like the Yellow Stem Borer (YSB), which causes substantial yield losses, especially in rice-dominant regions like Nepal. This study focuses on evaluating the effectiveness of biological, botanical, and chemical pesticides against YSB in spring rice crops of Ratuwamai, Morang, Nepal. For this, we apply biological methods/pathogens like Bacillus thuringiensis, to target YSB; botanical pesticides, derived from plants like Azadirachtin and Mugworth, act as repellents; while chemical pesticides such as Cypermethrin, Chlorpyriphos and Cartap Hydrochloride offer rapid control but come with environmental risks. Among those six pesticides used, the present findings revealed that chlorpyriphos 20% EC have minimum mean dead heart with 4.92% and cypermethrin 10% EC have minimum mean white ear head with 2.44% respectively after application of first and second dose of treatments respectively. Likewise, most plant yield attributes were superior where chlorpyriphos was used. Though bacillus and azadirachtin reduced the dead heart and white ear head symptoms, they couldn’t give good yield than that of chemical pesticides. Thence, through our research we investigated the impacts of different biological, botanical and chemical pesticides in controlling YSB population densities, and influencing yield and yield attributing characters from the field experiment.