Efficacy of current and potential grain protectant insecticides against a fenitrothion‐resistant strain of the sawtoothed grain beetle,Oryzaephilus surinamemisL

摘要

AbstractThe responses of a highly fenitrothion‐resistant and a susceptible strain of Oryzaephilus surinamensis L. from Australia were measured against a range of alternative grain protectants using impregnated‐paper and treated‐grain assays.The R‐strain was also highly resistant to carbaryl, moderately resistant to malathion and pirimiphos‐methyl and showed low‐level resistance to methacrifos, chlorpyrifos‐methyl, bioresmethrin, permethrin, cyfluthrin, cypermethrin and dichlorvos. There was marginal resistance to deltamethrin. Methoprene, to which there was no resistance, was the most effective material at suppressing progeny production of the resistant strain. At current commercial application rates chlorpyrifos‐methyl was the only compound of those tested that would completely control both adults and larvae of resistant O. surinamensis for a storage period of nine months.Overall, the homogeneity of response of both strains to insecticides using the treated‐grain assay was as good as the response from impregnated‐paper assays. The latter also tended to exaggerate resistance factors compared to the t