Naik_2026_Pestic.Biochem.Physiol_221_107179

The brown planthopper is a major rice pest in India and intensive insecticide use has led to widespread resistance development. To assess the current resistance status, we evaluated 14 field populations of Nilaparvata lugens collected from eight states across India against five commonly used insecticides - imidacloprid, dinotefuran, pymetrozine, triflumezopyrim and buprofezin- using rice stem dipping method during 2024-2025 at ICAR- Indian Institute of Rice Research, Hyderabad, India. The results revealed considerable variation in resistance levels among populations. Moderate to high resistance was recorded to imidacloprid (RR: 24.81-63.61) and buprofezin (RR: 11.85-56.53), particularly in Maruteru, Nalgonda, and Gangavathi populations. Dinotefuran (RR: 6.82-21.99) and pymetrozine (RR: 4.17-25.96) exhibited low to moderate resistance, while triflumezopyrim remained effective and recorded low resistance ratio (3.28-13.13 folds). Biochemical assays revealed significant elevation in detoxification enzyme activities among field populations. Cytochrome P450 monooxygenase activity was strongly correlated with resistance to imidacloprid, dinotefuran and buprofezin, indicating a central role of cytochrome P450 monooxygenases in metabolic resistance. Esterase activity exhibited a moderate and significant association with resistance to imidacloprid and triflumezopyrim, whereas glutathione S-transferase activity was significantly associated only with imidacloprid. Cluster analysis grouped populations into distinct biochemical clusters, indicating variability in metabolic resistance patterns among regions. The findings highlight increasing resistance in N. lugens populations and emphasize the importance of continuous resistance monitoring and integrated resistance management strategies for sustainable rice production.