Susceptibility to Endosulphan in the stink bug Piezodorus guildinii (Hemiptera: Pentatomidae) Westwood

Abstract

The stink bug Piezodorus guildinii Westwood (Hemiptera: Pentatomidae) is a key insect pest in soybeans in Uruguay. This species attacks in number of individuals that are capable to cause economic losses every year and thus, insecticides are needed for their control. There are a few insecticides available for the control of this insect, most of them, with a wide spectrum of action. Repeated applications of products with similar mode of action lead to insect resistance to insecticides. Adults of the stink bug were collected from a soybean area non-treated with insecticides and from commercial soybean crops sprayed more than one time with endosulphan. In the laboratory, the stink bug adults were kept under tarsal contact with the residue of a commercial formulation of endosulphan in the concentrations: 0, 4.375, 8.75, 17.5, 35, 70, 140, 280 and 560 mg a.i./L of water, in glass recipients of 0.8 L of volume. The most susceptible adults to endosulphan came from the non sprayed soybean area, while the insects collected in the commercial crops showed lower levels of susceptibility to the insecticide.