Residues of commercially used insecticides in the environment of Megachile rotundata [Alfalfa pollinator, Washington]

Residues of demeton, aldicarb, trichlorfon, dimethoate, and carbofuran (and their toxic metabolites) were determined in alfalfa leaf, pollen, and nectar, and in the pollen-nectar ball and leaf from the reproductive cell of M. rotundata F. The exposure of larvae to insecticide residue in the pollen-nectar ball from the bee cell averaged 17.6 ng of total insecticide for demeton, 0.4 ng of total insecticide for aldicarb, 148 ng for trichlorfon, and essentially 0 ng for dimethoate and carbofuran. The data showed no adverse effects on larvae by any of the residue found in various insecticides investigated.