The susceptibility of larvae of Dermestes L. (Coleoptera, Dermestidae) to some contact insecticides

The susceptibility of larvae of Dermestes lardarius L., and D. maculatus Deg. to 15 contact insecticides of relatively low mammalian toxicity was studied by a topical application method. Comparative tests were made on larvae of Alphitobius laevigatus (F.), and 8 of the compounds were tested against D. ater Deg. The organophosphorus compounds dimethoate, morphothion, chlorthion, dicapthon, fenitrothion, and fenthion were the most effective in killing Dermestes spp., and produced higher mortalities than pyrethrins, DDT or lindane. Dieldrin was the most effective compound used on D. maculatus, but it yielded neglighible mortalities with D. lardarius and D. ater. Malathion was effective against D. lardarius but not against D. maculatus. A. laevigatus larvae were susceptible to a wider range of compounds than those of Dermestes spp. Some of the insecticides disturbed the metamorphosis of mature Dermestes larvae.