Published online by Cambridge University Press: 31 May 2012
Adults of predatory carabid beetles (Coleoptera: Carabidae) of the species Stenolophus comma Fabricius field-collected from light traps were bioassayed against several soil insecticides along with laboratory reared larvae of the predatory carabid Pterostichus melanarius Illiger. Adult S. comma beetles were exposed to serial dilutions of insecticides using a Potter spray tower; larvae of P. melanarius were exposed to insecticidally treated Plainfield sand. Fensulfothion, phorate, methomyl, carbofuran, and O,O-diethyl-S(tertbutylthio) methyl phosphorodithioate (Counter®) proved to be highly toxic to adult S. comma with a 0.01% solution causing mortalities > 65%. In the bioassay of P. melanarius larvae, Counter®, phorate, heptachlor, aldrin, and O-(2-chloro-1-(2,5-dichlorophenyl)vinyl) O-methyl ethylphosphonothioate (WL 24073) produced mortalities > 75% at 0.1 p.p.m. in Plainfield sand. The Pterostichus larvae which are probably important as predators of pest insects appear quite susceptible to several important soil insecticides. Chlorfenvinphos, leptophos, and p,p′-DDT were fairly innocuous to both adults and larvae.