Anber_1988_Pestic.Biochem.Physiol_31_91

Evidence was obtained for the presence of at least two genes for high parathion resistance in an Italian strain of Amblyseius potentillae. The isolation of one of the genes in a substrain, A, is described. The S and A strains have an acetylcholinesterase activity of 0.71 and 0.35 nmol/mite/hr, respectively for acetylthiocholine. The rate of inhibition is greatly reduced in the A strain, being 781-fold lower for propoxur, 311 for paraoxon, 61 for tetrachlorvinphos, 21 for omethoate, and 19 for azinphos-methyl PO analog. The mutant of this predatory mite and that of the spider mite Tetranychus urticae are much more insensitive to paraoxon than insect-resistant acetylcholinesterases. The level of resistance in the A strain was measured on residues of pure insecticides and varies from 40-fold for omethoate to 41,000-fold for paraoxon. The correspondence between insensitivity of the enzyme and degree of resistance is discussed.