The impact of rice straw incorporation and insecticide application on brown planthopper, Nilaparvata lugens Stal. (Hemiptera: Delphacidae) population and beneficial insects

Integrating rice straw incorporation and insecticide application is an agricultural practice with significant implications for pest management and ecosystem health. This study explores the combined effects of these practices on the brown planthopper (BPH) population, Nilaparvata lugens Stal., a major rice pest, and on beneficial insects that contribute to natural pest control. Two experiments were conducted in Ciwaringin, Lemahabang, Karawang, West Java, from January to September 2022 during the rainy seasons. The field trial used a split-plot design with two main plots: rice fields with and without rice straw incorporation. Additionally, there were three subplots: no insecticide, fipronil as a broad-spectrum insecticide, and triflumezopyrim as a narrow-spectrum insecticide. The first insecticide application was triggered at the economic threshold level. BPH and beneficial insect populations were sampled every two weeks using suction devices and insect nets. Direct BPH population observations were conducted weekly to determine insecticide application timing. Incorporating rice straw alone reduced BPH populations and increased the number of beneficial insects, particularly predators. In contrast, insecticide application significantly decreased BPH populations but caused substantial mortality among beneficial insects. Specifically, fipronil use was associated with a marked reduction in parasitoid populations. Moreover, the beneficial effects of straw incorporation on BPH and predator populations were not observed when insectiside triflumezopyrim was applied.