Resistance of hairy fungus beetle (Coleoptera: Mycetophagidae) to pirimiphos methyl and malathion

Adult hairy fungus beetles, Typhaea stecorea (L.), were collected in Livingston County, Ill., from stored corn treated with pirimiphos methyl. When compared with a susceptible population exposed for 14 d to insecticide residues on corn in laboratory bioassays, the Livingston County population exhibited 38-fold resistance to pirimiphos methyl and 66-fold fold resistance to malathion at the LC50. This is the first report of insecticide resistance in the hairy fungus beetle. A laboratory colony of the red flour beetle, Tribolium castaneum (Herbst), showed resistance to malathion but not cross-resistance to pirimiphos methyl. A laboratory colony of the maize weevil, Sitophilus zeamais Motschulsky, was susceptible to both insecticides