The Neotropical brown stink bug, Euschistus heros (F.), is usually controlled by organophosphate (OP) and cyclodiene (endosulfan) insecticides. Some unsuccessful control cases lead us to search for resistance to these insecticides in E. heros, the most common stink bug in the soybean growing regions of Paraná State, São Paulo State and Central Region of Brazil. Bioassays were performed with endosulfan, monocrotophos and metamidophos against adults. The most susceptible population was found in Londrina. Populations from Pedrinhas Paulista (SP) showed the highest resistance ratio (RR) to endosulfan (RR= 8.7) and metamidophos (RR=2.7); resistance to monocrotophos was detected on bugs from Centenário do Sul (PR) (RR= 3.1). Stink bugs collected from Toledo (PR), showed susceptibility to metamidophos comparable to those from Londrina.
Insecta; organophosphate; cyclodiene; soybean
