Effects of Diflubenzuron (Dimilin®) on Selected Beneficial Arthropods in Cotton Fields 12

Abstract

Populations of the arthropod predators, Geocoris punctipes (Say), Nabis spp., Hippodamia convergens Guerin, Coleomegilla maculata (DeGeer), Orius insidiosus (Say), Chrysopa spp., and Araneida, were monitored in cotton fields treated with diflubenzuron, in cotton fields treated with conventional insecticides, and in cotton fields to which no insecticides were applied. G. punctipes and H. convergens were taken from both diflubenzuron-treated and untreated fields to the laboratory to study oviposition and egg hatch. With the exception of G. punctipes , reduction of predator populations in diflubenzuron-treated fields vs. untreated fields was not significant. This was in marked contrast to the highly adverse effects of conventional insecticides upon the predator populations. For 6 days after collection, egg hatch in laboratory-held H. convergens was significantly lower in females collected from diflubenzuron-treated cotton fields than in those from untreated fields. Additional differences in fecundity were not detected in the laboratory studies.