Increases of Heliothis1 spp. in Cotton Under Various Insecticide Treatment Regimes2

Abstract

During the summer of 1974 in the Imperial and Palo Verde Valleys of southern California, population densities of arthropod predators and Hetiothis spp. were studied after insecticide treatments for the pink bollworm. Geocoris spp., Orius tristicolor (White) and spiders were the most numerous arthropod predators. Chrysopa carnea Stephens and Collops marginellus LeConte were least affected by increased insecticide usage. The mean density of arthropod predators was significantly reduced while the mean density of Heliothis spp. was significantly increased by increased insecticide usage.