D. Collins, D. Cook
Aug 1, 1998
Citations
0
Influential Citations
14
Citations
Journal
Crop Protection
Abstract
Abstract The periods of protection provided by emulsifiable concentrate (EC), dust (DP), microcapsule suspension (MS) and ultra low volume (UL) formulations of pirimiphos-methyl, and EC and DP formulations of etrimfos, were assessed at 25 °C and 70% relative humidity (r.h.), when admixed with wheat at 0.5, 1, 2 and 4 mg kg −1 , against susceptible Tribolium castaneum (Herbst), Oryzaephilus surinamensis (L.), Sitophilus granarius (L.) and Rhyzopertha dominica (F.). One day and 1 week after treatment and then every 4 weeks for 36 weeks, samples of wheat were taken for pesticide residue analysis and insect bioassays. Insect mortality was assessed after 1, 7, 14, 21 and 28 days exposure. Against T. Castaneum, O. surinamensis and S. granarius the MS formulation of pirimiphos-methyl provided the longest periods of protection with shorter exposures required for complete mortality. The etrimfos DP was most effective against R. dominica . A reduction in etrimfos residues was detected over the 36 weeks, with pirimiphos-methyl residues fluctuating slightly, though a loss in biological effectiveness was observed.