Dermal Efficacy Evaluation of New Insecticides for Control of Plum Curculio in Peaches

Abstract

Labeled rates of bifenthrin (Capture® 4EC, 112 mg a.i. ha-1), fipronil (Regent® 4SC, 280 mg a.i.-ha-1), malathion (Bonide® 50% Malathion, 560 mg a.i.-ha-1), thiacloprid (Calypso® 4EC, 288 mg a.i.-ha-1), thiamethoxam (Actara® 25WG, 87 mg a.i.-ha-1), and twice the labeled rates of these same insecticides, were examined (along with an untreated control) for dermal efficacy against plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae). Plum curculios treated with labeled rates of fipronil, bifenthrin, and malathion exhibited higher mortality (by no later than 96 hours post-application) than plum curculios left untreated or treated with labeled rates of thiamethoxam and thiacloprid. At 24 h post-application, malathion at the labeled rate, malathion at twice the labeled rate, and bifenthrin at twice the labeled rate resulted in > 90% efficacy. Fipronil at twice the labeled rate produced an acceptable level of control (≤90% mortality) by 48 h post-application. This rapid laboratory method of assaying new insecticides shows promise for selecting insecticides capable of producing dermal toxicity for subsequent field evaluation.