Optimizing Thresholds and Reduced-Risk Management Strategies for the Control of SWD in Maine's Wild Blueberries

View the project final report

Commodities

• Fruits: berries (blueberries)

Practices

• Pest Management: integrated pest management

First detected in Maine in 2011, the invasive spotted-wing drosophila, Drosophila suzukii (Matsumura), also known as SWD, has since become a severe economic pest in lowbush (wild) blueberry (Vaccinium angustifolium Aiton).  Female SWD have a hardened serrated ovipositor with which they deposit eggs in ripening berries.  Lowbush blueberry is a valuable native economic crop in Maine, contributing over $250 million to the state's economy each year.  SWD have the potential to cause lowbush blueberry revenue losses in excess of $6.8 million per year.  Current management practices in lowbush blueberry involve early harvesting (yield loss from underripe fruit), increased insecticide applications (expensive, environmentally harmful, and may lead to resistance), or no management (yield loss from infested fruit).  This project aims to improve SWD management in Maine's lowbush blueberries by enhancing risk-based action thresholds and exploiting the pest's perimeter behavior.  Current action thresholds based on adult SWD trap captures will be enhanced by increasing the traps' efficiency and retention rates. It is expected this will allow growers to better time implementation of SWD management measures.  Management through the exploitation of perimeter behavior will entail border insecticide applications and the implementation of attract and kill strategies, leading to a reduction of insecticide input into the agroecosystem.  This project's results will be shared with Maine lowbush blueberry growers at extension and outreach meetings and presented at the 2022 Entomological Society of America meeting.

1) Optimization of trap captures and threshold modeling.

Objective (1) will entail testing the efficiency of six different styles of SWD monitoring traps, and the incorporation of these different style trap captures into a risk-based action threshold model to help growers determine the ideal timing for management strategy implementation.

2) Exploration of reduced-risk management strategies. 

Objective (2) will involve assessment of the efficacy of insecticide border applications in large scale field trials, compare the efficacy of multiple behavioral control and push-pull tactics in field cages, and a field and semi-field bioassay assessment of a phagostimulatory adjuvant.