A laboratory evaluation of pirimiphos methyl and difluron admixed with wheat against the granary weevil

Abstract

were tested against the granary weevIl (Sltophtll~S granartliS (1:.». Pmmlphos methyl, LC95 0.75 ppm, was con sidera~ly more a~tIve. than maldlso.n, LC95 3.4 ppm. As difluron acts by inhibiting c.utIcle .r~rmatIon, It was n?t active against adult weevils. Insecticide concentrations glvmg a 95%. r~d~ctlOn in the Fl generation population over the control treatm~n~s,. were: pmmlphos methyl 0.5 ppm, difluron 1.9 ppm, and maldison 2.0 ppm. Pmf!1lphos methyl was the most cost effective compound tested. A method for assessmg the evenness of distribution of insecticide dust through grain is also presented.