Monitoring of Insecticide Resistance on Brown Planthopper (Nilaparvata lugens (Stål)) Population in Northeastern Region of Thailand

Abstract

The brown planthopper, or Nilaparvata lugens ( Stål) , is important insect pest that affects rice throughout all growth stages and has been found to be widely spreading. Using insecticides was one common strategy, however if dubious scientific practices were used, BPH may develop resistance to the pesticides. The study aimed to investigate insecticide resistance in the BPH population in the northeastern region of Thailand in 2023. BPH populations were collected from rice fields in four provinces of northeastern area: Nong Khai, Khon Kaen, Sakon Nakhon and Ubon Ratchathani. Utilizing the topical bioassay method, three common agricultural insecticide types imidacloprid, dinotefuran, and ethiprole were tested for resistance levels based on their toxicity values (LD50) against populations of brown planthoppers. According to the experiment's findings, BPH populations in each of the four provinces had resistance ratios ranging from 1. 00 to 4. 41, indicating that they have not yet adapted to these three insecticides. In Nong Khai Province, imidacloprid showed the highest LD50 value, measuring 2.273 micrograms per gram. In Khon Kaen Province, dinotefuran had the highest LD50 value at 0. 127 micrograms per gram, whereas in Ubon Ratchathani Province, ethiprole had the highest LD50 value at 0. 718 micrograms per gram. This resistance monitoring information might be a useful guide for selecting insecticides for the safe and effective management of BPH.