Baseline susceptibility of brown planthopper (Nilaparvata lugens) populations to mesoionic insecticide triflumezopyrim in Southern India

The brown planthopper (BPH), Nilaparvata lugens (Stål.), poses a significant threat to rice cultivation, acting as a key pest. The emergence of resistance to various insecticide classes has emerged as a prominent challenge, significantly hindering the effective management of N. lugens . Triflumezopyrim, a novel mesoionic chemistry insecticide, has recently been introduced in India for controlling N. lugens . Establishing the baseline susceptibility and monitoring its effectiveness throughout the life cycle of the molecule are crucial aspects for a newly commercialized insecticide like triflumezopyrim. In this study, the baseline toxicity of triflumezopyrim against brown planthopper populations from nine hotspot locations in three southern states of India was evaluated using the rice seedling dip method. The LC 50 values varied between 0.123 and 0.268 mg/L, showing a 2.18-fold variation. This information holds significance in monitoring potential changes in N. lugens susceptibility to triflumezopyrim in the future, thereby assisting in the formulation of effective management strategies.