Effects of registered and experimental insecticides on Lygus hesperus and on selected beneficial arthropods in California cotton

摘要

Selected registered and experimental insecticides were compared in terms of efficacy on Lygus hesperus, effects on beneficials, and potential to flare secondary arthropod pests in 1998 and 1999. Of the registered materials, the pyrethroids provided excellent Lygus bug control; however, the residual was only between 7 and 14 days. The organophosphate products and Provado gave good, but short-term control. Vydate, (tested in 1999 only), performed well. Regent appears to provide Lygus bug control in the same range as the pyrethroids. Provado had the least effects of the tested materials on natural enemies. The pyrethroid insecticides effected natural enemies severely for the first several days following application. The relatively small plot size and effects of the materials on populations of other arthropods, i.e., potential prey, made it difficult to evaluate long-term effects. The organophosphate insecticidal effects on natural enemies were erratic. Regent had a moderate to severe effect on beneficials. In addition, populations of spider mites increased significantly following Regent application in 1998; these effects in 1999 were more moderate. Regent appears to have potential to flare secondary pests such as spider mites. Several other tested materials also increased spider mate densities, especially in 1998, and to a reduced extent, in 1999.