EFFECT OF CHLORPYRIFOS AND CYPERMETHRIN APPLICATIONS ON NONTARGET INVERTEBRATES IN A CONSERVATION-TILLAGE CROP

The short-term impact of two commonly used insecticides (chlorpyrifos and cypermethrin) on predatory species of invertebrates, including car abid beetles (Coleoptera: Carabidae), wolf spiders (Araneae: Lycosidae ), Labidura truncata Kirby (Dermaptera: Labiduridae) and a pest beetle , Gonocephalum adelaidae Blackburn (Coleoptera: Tenebrionidae), was as sessed in a faba bean crop (Vicia faba L. cv. Fiord) grown under conse rvation-tillage. The project aimed to identify which, if any, of the k ey beneficial or pest invertebrates that are active on the soil surfac e were affected by foliar applications of insecticides. The activity o f some species, reflected by numbers of pit Fall trapped individuals, was affected within 24 h. There was a brief (1-d) increase, followed b y a reduction in the number of G. adelaidae, L. truncata and carabids captured in the cypermethrin sprayed plots when compared to the contro l and chlorpyrifos treatments. The numbers of carabids captured declin ed in both insecticide treatments for the remainder of the study perio d, but neither treatment had any observed effect on G. adelaidae, L. t runcata or lycosid spiders.