Relative Susceptibility of Attagenus alfierii1 and A. megatoma1 Larvae to Several Organophosphorus Insecticides2

The susceptibility of Attagenus alfierii Pic and A. Megatoma (F.) to 12 insecticides was determined by direct application of spray solutions to mature larvae. The order in effectiveness at LC95of insecticides tested against A. alfierii was: fenitrothion (O,O-dimethyl O-4-nitro-m- tolyl phosphorothioate) > dicapthon > chlorphoxim > fenthion > dichlorvos > phoxim > C-9491 (O- (2,5-dichloro- 4-iodophenyl) O,O-dimethyl phosphorothioate) malathion > Dursban® (O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate) > Abate® (O,O-dimethyl phosphorothioate O,O-diester with 4,4'-thiodiphenol) > Gardona® (2-chloro-I-(2,4,5-trichlorophenyl)vinyl dimethyl phosphate) > diazinon. The order of effectiveness against A. megatom A was: dicapthon > fenthion > fenitrothion > chlorphoxim > phoxim > Dursban > malathion> diehlorvos > C-9491 > diazinon > Gardona > Abate. At LC50 and LC50,dicapthon and Dursban were slightly more effective against A. megatoma than A. alfierii, while all other compounds, except malathion, were more effective against A. alfiaii than A. megatoma. Differences between species in susceptibility to each insecticide ranged from being practically equal for malathion to X 6.6 for Abate at LC95.