Submitted to: Journal of Economic Entomology
Publication Type: Proceedings
Publication Acceptance Date: August 1, 2000
Publication Date: N/A
Interpretive Summary: Conservation of insect natural enemies is a desirable component of integrated pest management (IPM). Cotton, in particular, often receives several applications of insecticides that can disrupt natural enemies. Information on the lethal and sublethal effects of various cotton insecticides to key beneficial species is therefore important in selection of compounds that will minimize mortality. Two insect predators, the big- eyed bug and the insidiosus flower bug, were evaluated in a residual insecticide bioassay to ten insecticides including four with novel modes of action. Spinosad, an insecticide targeted for foliage-feeding insects, and the insect growth regulator,tebufenozide, were less toxic than chlorfenapyr to big-eyed bug. Tebufenozide was less toxic to the insidious flower bug than chlorfenapyr. Malathion was highly toxic to both species. Fecundity and pest egg-consumption by both beneficial species were significantly reduced by several insecticides, including malathion. Cotton IPM is highl complex and relies on many factors. However, any understanding we can gain regarding the selectivity of pesticides will be beneficial. It is particularly important to obtain data on the new insecticides with novel modes of action, because these may replace conventional insecticides for use on resistant pest insects. The importance of observing direct mortality and sublethal effects of insecticides on beneficial arthropods is discussed.
Technical Abstract: Adults obtained from laboratory cultures of the insidiosus flower bug, Orius insidiosus, and big-eyed bug, Geocoris punctipes, were exposed to ten insecticides, including three newer insecticides with novel modes of action, using a residual insecticide bioassay. There was considerable variation in response among both species tested to the insecticides. Tebufenozide and cyfluthrin were significantly less toxic to male O. insidiosus than malathion. Tebufenozide was also significantly less toxic to female O. insidiosus than malathion. Imidacloprid, tebufenozide and spinosad were significantly less toxic to make G. punctipes than chlorfenapyr, endosulfan and fipronil. Spinosad, tebufenozide, and azinphos-methyl were significantly less toxic to female G. punctipes than fipronil and endosulfan. Fecundity of O. insidiosus was significantly greater in the spinosad treatment compared with other treatments, including gthe control. Consumption of bollworm, Helicoverpa zea (Boddie) eggs by O. insidiosus was significantly lower in the fipronil, profenofos and cyfluthrin treatments compared with other treatments,including the control. Consumption of H. zea eggs by G. punctipes was significantly lower in the malathion, profenofos, endosulfan, fipronil, azinphos-methyl and imidacloprid treatments compared with the control. Egg consumption by G. punctipes was not significantly different in the tebufenozide treatment compared with the control. The lower toxicity of spinosad to G. punctipes is consistent with other reports.