EFFECTS OF SEVERAL TYPES OF INSECTICIDES ON THE MITE PREDATOR, STETHORUS-PUNCTUM (COLEOPTERA, COCCINELLIDAE), INCLUDING INSECT GROWTH-REGULATORS AND ABAMECTIN

Abamectin, methomyl, several types of insect growth regulators (IGRs), and several organophosphate insecticides were evaluated for toxicity to the egg, larval, pupal, and adult stages of the coccinellid mite predator, Stethorus punctum (LeConte). Field-collected eggs were dipped into aqueous solutions to evaluate ovicidal activity; field collected mid-instars and adults were tested by a 24-h dry film exposure method. Multiple mortality readings were done over time. Pupal mortality was evaluated in field plots that received biweekly applications. Fenoxycarb was ovicidal in the laboratory and disrupted the larval-pupal molt in the field. Abamectin was toxic to S. punctum larvae and adults in the laboratory and methomyl was toxic to adults. Teflubenzuron was toxic to the pupal stage in the field; along with fenoxycarb, this IGR caused late-season increases of phytophagous mite populations in field trials. Tebufenozide was not toxic to all S. punctum stages in the laboratory and field. S. punctum was tolerant to all organophosphate insecticides tested.