Spotted wing drosophila (SWD) is a major insect pest of small fruit and tree fruit crops, as they lay eggs in ripe fruit. Infestation risk factors include high canopy humidity, and ripe and over-ripe fruit (hanging, dropped or rejected). Following the guidelines below will help to achieve the best possible SWD management.
- Before new plantings, select varieties carefully. Advantages for SWD management include earlier ripening berries and even berry development for uniform harvesting.
- Manage Himalayan blackberries, which provide habitat for SWD. Try to remove prunings to avoid regrowth, and be aware of bylaw and label restrictions regarding herbicide use.
- Record hot-spots based on previous high trap catches and infested fruit.
- Learn to use a degree day model to predict when SWD will become active in the spring.
- Prune bushes to open the canopy, decrease humidity, improve harvest efficiency, and improve spray coverage and penetration.
Growing Season to Harvest
- Cut back and/or prune flowers or green fruit from any Himalayan blackberries near fields.
- See BCBC IPM Newsletter for spring and summer SWD trap catches, which will help determine level of SWD risk in the area, and whne insecticide treatments could optimally begin.
- Harvest berries early and often leaving as little ripe fruit as possible.
- Cool or freeze fruit as soon as possible after harvest to slow growth or kill eggs and larvae.
- Sample for larvae in fruit by using the ‘float out’ method to determine infestation level.
- (see Fact Sheet pdf)
Post-Harvest to Dormancy
- Destroy all culled fruit
- Clean equipment and fruit processing areas
- Repair leaking irrigation lines, and/or modify to drip irrigation, rather than over-head, to reduce humidity.
- Apply or repair weed mats – in summer, they may kill SWD that drop onto the hot surface
- Install or repair trellis wires – Crop training allows better spray coverage and fewer berries are knocked off bushes during spraying
- Place SWD traps in hedgerows and field edges. Monitor for over-wintering hot spots to predict SWD movement inot field for next season.
Rotating Between Pesticides (see pdf)
Degree Day Model (see pdf)
Links and Resources (see pdf)