Efikasi Lapang Berbagai Insektisida Untuk Mengendalikan Ulat Grayak (Spodoptera Exigua) Dan Pemantauan Keragaman Insekta Pada Agroekosistem Bawang Merah (Allium Cepa L.)

Spodoptera exigua is one of the major pests of shallot crops and can cause severe leaf damage leading to yield losses. Chemical control using insecticides is widely applied. However, it may also affect on insect diversity in shallot agroecosystems. The research was conducted from November 2025 to January 2026 at the experimental research of PT Petrokimia kayaku, kediri, East Java. A randomized Complete Block Design (RCBD) consisting of ten treatments and three replications was employed. Observed variables included pest attack intensity, insecticide efficacy, fresh bulb yield, and insect diversity using yellow sticky trap. The results showed insecticide application significantly affected pest attack intensity during the early observation period but had no significant effect in subsequent observations. The highest efficacy at 17 days after planting was obtained from chlorfenapyr 180 g/L + indoxacarb 120 g/L at 1000 ml/ha with an efficacy value of 63%, which did not meet the effectiveness threshold (>70%). At the final observation, efficacy values of all treatments declined to 0–1%. The highest fresh yield was recorded in the treatment of isoflualanam 40 g/L + methoxyfenozide 160 g/L at 1125 ml/ha, reaching 31.58 kg, while the lowest yield was observed in isocycloceram 200 g/L at 1000 ml/ha with 15.65 kg. Insecticide application also reduced the number of insects captured, with Diptera remaining the dominant order, decreasing from 9,410 individuals before application to 152 individuals after application. The Shannon-Wiener diversity index (H') was categorized as low (<1), indicating that the insect community was dominated by a few insect orders.