| Tree fruit growers are seeking effective alternatives to US EPA-mitigated insecticides for managing plum curculio, Conotrachelus nenuphar Herbst (Coleoptera: Curculionidae). Formulations and novel delivery mechanisms of entomopathogenic nematodes (Steinernema riobrave, Steinernema carpocapsae and Heterorhabditis bacteriophora) and fungi ( Beauveria bassiana and Metarhizium anisopliae) were investigated in the laboratory and in Michigan orchards. Mortality of fungus-exposed adults ranged from 38-100% and occurred 17-23 d post treatment in the laboratory. Fall granular fungus formulation applications failed to reduce overwintering survival of adults. Larvae were introduced to orchard soils -10, -5, 0, 5, 10, 15, or 20 d from entomopathogen application. Steinernema riobrave consistently reduced adult emergence most effectively in sandy sites. Beauveria bassiana exhibited limited effectiveness and sensitivity to environmental and site factors. Both nematodes and fungi were promising tactics against plum curculio, but more investigation is needed to determine if oviposition damage and the second generation can be reduced to economic levels. |
