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 carabid beetles (Coleoptera: Carabidae), wolf spiders (Araneae: Lycosidae), Labidura truncata Kirby (Dermaptera: Labiduridae) and a pest beetle, Gonocephalum adelaidae Blackburn (Coleoptera: Tenebrionidae), was assessed in a faba bean crop (Vicia faba L. cv. Fiord) grown under conservation-tillage. The project aimed to identify which, if any, of the key beneficial or pest invertebrates that are active on the soil surface were affected by foliar applications of insecticides. The activity of some species, reflected by numbers of pit Fall trapped individuals, was affected within 24 h. There was a brief (1-d) increase, followed by a reduction in the number of G. adelaidae, L. truncata and carabids captured in the cypermethrin sprayed plots when compared to the control and chlorpyrifos treatments. The numbers of carabids captured declined in both insecticide treatments for the remainder of the study period, but neither treatment had any observed effect on G. adelaidae, L. truncata or lycosid spiders.