Spotted wing drosophila (SWD), a highly invasive pest of small fruits such as blueberries and raspberries, causes significant yield losses. Females have serrated ovipositors, allowing them to lay eggs in unripe fruits, making them unsellable. High fecundity and short generation time also contribute to the challenges in managing this fly. Current management heavily relies on using broad-spectrum insecticides, which increases its resistance. Recently, there has been an increasing interest in biological control and other sustainable tactics to reduce reliance on insecticides. This study investigates the potential of using entomopathogenic nematodes (EPNs) and entomopathogenic fungi (EPF) as alternative control methods. Lab experiments in 2022 and 2023 tested commercially available EPNs and EPFs against SWD's soil-dwelling stages. Nine EPN species and three EPF species were assessed at various concentrations against the soil-dwelling stages of SWD. Results showed that three EPN species (Steinernema feltiae, Steinernema carpocapsae, and Steinernema glaseri) and one EPF species (Beauveria bassiana) reduced SWD mortality by more than 50%. When combined, EPF and EPNs achieved more than 90% reduction. Although these findings suggest that EPNs and EPF may not wholly control SWD populations, they could be beneficial additions to SWD management strategies.
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