Carbaryl Resistance in Native and Released Populations of Amblyseius fallacis12

Susceptibility data taken from mites originating from 11 commercial apple orchards in Michigan indicated that resistance to carbaryl in populations of Amblyseius fallacis is presently low even in blocks receiving light or moderate applications of this insecticide. Only when multiple, within-season applications (3–5/season) and consecutive yearly treatments (4–9 years) are maintained does a significant resistance develop which can have practical application in an integrated mite control program. Toxicological data were taken from predatory mites after organophosphate, carbamate and multiple organophosphorus and carbaryl-resistant strains were released separately into apple trees lacking native populations of this species. All trees received alternating treatments of azinphosmethyl and carbaryl the first year after the release of predators and only azinphosmethyl the 2nd year. Data indicated that predators were readily established, but in contrast to organophosphorus resistance, carbaryl resistance did not persist in mite populations after the above insecticide applications were applied.