Efficacy of commercially available predators, nematodes and fungal entomopathogens for augmentative control of D rosophila suzukii

The recent arrival of D rosophila suzukii , an invasive pest of soft‐skinned fruit with a wide host range, has resulted in increased production costs for growers and the need for additional insecticide applications each growing season. There are few effective organic insecticides for D . suzukii , and insecticide use in conventional farms may be disruptive to natural enemies, suggesting a need for effective biological control to combat D . suzukii . Commercially available natural enemies were evaluated for their potential use in augmentative releases, including: the predators O rius insidiosus and D alotia coriaria ; the entomopathogenic fungi M etarhizium anisopliae , B eauveria bassiana and P aecilomyces fumosoroseus ; and the entomopathogenic nematodes H eterorhabditis bacteriophora , S teinernema feltiae and S . carpocapsae . This suite of natural enemies was chosen to target D . suzukii adults as well as larvae in hanging or dropped fruit. Of the cultured fungal strains tested, only M . anisopliae significantly decreased D . suzukii survival, but it had low residual activity and no effect on D . suzukii fecundity. O . insidiosus decreased D . suzukii survival in simple laboratory arenas but not on potted blueberries or bagged blueberry branches outdoors. D . coriaria did not decrease D . suzukii survival in infested blueberries in simple laboratory arenas. The nematodes tested showed low infection rates and were not able to affect D . suzukii survival. Although this suite of natural enemies showed limited ability to suppress D . suzukii under the tested conditions, these and related natural enemies are present as part of the endemic natural enemy community in agricultural fields, where they may contribute to D . suzukii suppression.