EVALUATION OF PROTECTANTS FOR CONTROL OF ACANTHOSCELIDES-OBTECTUS (SAY) (COLEOPTERA, BRUCHIDAE) IN NAVYBEANS (PHASEOLUS-VULGARIS (L))

Five organophosphorus compounds (OPs), one carbamate, five synthetic p yrethroids (SPs) and three insect growth regulators (IGRs) were tested against the bruchid Acanthoscelides obtectus (Say) in navybeans (Phas eolus vulgaris L.) stored in the laboratory. Activities of the insecti cides varied greatly in short-term assays with the IGRs having low pot ency. Four OPs (fenitrothion, chlorpyrifos-methyl, pirimiphos-methyl a nd methacrifos) and two SPs (permethrin and deltamethrin) were assesse d further during 36 weeks storage at 30-degrees-C, 70% r.h. The OPs lo st activity rapidly during storage compared to the SPs. Pirimiphos-met hyl, permethrin and deltamethrin gave the best results. Estimated rate s of application to give 36 weeks protection are 10-25 mg kg-1 of piri miphos-methyl, 0.2-0.5 mg kg-1 of deltamethrin, or 1-1.5 mg kg-1 of pe rmethrin.