Monday, December 10, 2007 - 9:41 AM

Curative activity of insecticides targeting immature life stages of plum curculio (Conotrachelus nenuphar Herbst) (Coleoptera: Curculionidae)

Eric J. Hoffmann, and John C. Wise, Michigan State University, Department of Entomology, 205 Center for Integrated Plant Systems, East Lansing, MI

Insecticidal effects on egg and larval stages of Plum Curculio, Conotrachelus nenuphar Herbst, were studied in both the laboratory and the field. Insecticides tested were from the organophosphate, pyrethroid, oxadiazine and neonicotinoid classes. Laboratory trials involved in vitro incubation of eggs in insecticide solutions and rearing of neonates on artificial diet that had been spiked with insecticide. In field trials, mated females were caged on tart cherry (Prunus cerasus) branches and allowed to oviposit on fruit for 48h. Branches were treated with a foliar spray, and larval emergence was counted daily. Laboratory in vitro trials identified ovicidal and larvicidal compounds from all tested classes, but only the organophosphate and neonicotinoid classes demonstrated effects in field trials using manufacturers’ labeled rates. Residue analysis by GC/MS or HPLC shows that some compounds are unable to penetrate the fruit cuticle sufficiently to reach the lethal concentrations determined in the laboratory assays. A curative approach may become a viable management tactic in light of the regulatory phaseout of the adult-targeted organophosphates.

Species 1: Coleoptera Curculionidae Conotrachelus nenuphar (plum curculio)
Species 2: Rosalis Rosaceae Prunus cerasus (tart cherry, sour cherry)