Heteropterans pests of cotton in the Brazilian Cerrado

The reduced use of insecticides in cotton due to Bt variety adoption and boll weevil suppression, allied with more narrow-spectrum insecticide use, are increasing the importance of heteropterans pests of cotton in the Brazilian Cerrado, especially of the stink bugs coming from soybean. During three growing seasons (2007/2008, 2008/2009 and 2009/2010), in replicated field plots, the heteropterans pests incidence was measured on a Bt-cotton variety (MON531) and on its near-isogenic non-Bt variety surrounded by soybean, in Dourados, Mato Grosso do Sul State, Brazil. In the first two growing seasons, for both varieties, the most abundant species were the pentatomids Euschistus heros (F.), Edessa meditabunda (F.) and the mirid Niesthrea sidae (F.), representing more than 90% of the incident species. Despite the greater number of E. heros adults compared with E. meditabunda adults, the opposite was observed for the nymphs, suggesting higher adaptation of this species to colonize Bt and non-Bt cotton. The heteropterans pests populations increased as soybean matured.