Reducing Drosophila suzukii Management Challenges: An Alternative to Insecticide Cover Sprays

View the project final report

• 2013 annual report

Commodities

• Fruits: berries (blueberries), berries (other)

Practices

• Crop Production: food product quality/safety
• Education and Training: extension, on-farm/ranch research, workshop
• Energy: energy conservation/efficiency
• Farm Business Management: budgets/cost and returns, risk management
• Pest Management: chemical control, field monitoring/scouting, integrated pest management

Spotted wing drosophila (SWD), Drosophila suzukii, is a new invasive pest capable of causing yield losses of 0-80% in berry and stone fruits. Female flies lay eggs inside ripening fruit in which larvae develop and feed. Since its discovery in the U.S. in 2008, growers minimize crop losses by repeated cover sprays of broad spectrum insecticides, significantly increasing production costs, disrupting existing IPM programs and potentially causing inadvertent environmental impacts. We propose implementing a strategy that targets the blueberry field border to prevent SWD migration from the surrounding unmanaged perimeters. In 2011 preliminary trials, insecticides applied only to blueberry field borders effectively prevented fruit infestation, despite high SWD numbers in surrounding Himalayan blackberries (HB). We propose performing replicated studies to determine the efficacy of border sprays for SWD management and to assess its potential to conserve aphid natural enemies. Growers are concerned about aphid flare-ups due to a reduction in their natural enemy populations from increased insecticide use. Aphids are a key pest, particularly in Washington and British Columbia where they vector blueberry scorch virus. In addition to the entomological implications, traveling with tractor and spray equipment down blueberry rows causes estimated fruit loss from knockdown of 5-10% with each application. Border sprays would mitigate this problem, as the tractor and spray equipment travel around the edge of the field. If effective, border sprays will reduce chemical use and alleviate risks to the environment and humans. Novel IPM tactics developed from this project will need to be adopted by industry. To assist with knowledge transfer, trial sites are being performed on-farm with a prominent stakeholder where we can host demonstration field days on a yearly basis. All research results will be regularly extended to growers and stakeholders through newsletters, berry extension websites, demonstration trials, outreach field days and grower meetings.

I. Determine the effectiveness of border sprays for SWD management and resulting reductions in yield loss due to fruit knockdown.

II. Quantify the effect of border sprays on a secondary pest (aphids) and their natural enemies.

III. Disseminate results of these studies to growers throughout the region using field days, meetings, newsletters and berry extension websites as well as publishing findings in scientific journals.