2025 Volume 67 Pages 10-14
This study examined the toxicity of five insecticides used to control overwintering adults of the brown rice stink bug Niphe elongata, an agricultural pest insect causes sterile rice. Overwintering adults of N. elongata were collected from three sites in southern Shiga Prefecture in July 2024. The effectiveness (corrected mortality) of each insecticide was evaluated using the adult-dipping method, complemented by a Bayesian model to control for sex-based differences in insecticide response. Results indicate that ethiprole, etofenprox, dinotefuran, and sulfoxaflor (each at 100 ppm) were highly toxic, achieving over 80% corrected mortality within 24 hours after exposure. Flupyrimin (100 ppm) showed lower toxicity than other insecticides in two strains. In all strains, it was also less toxic to females than in to males. Some adults initially affected by flupyrimin exhibited recovery, corrected mortality at 72 hours after exposure was lower than at 24 hours.
