Spotted Wing Drosophila Factsheet (2018)

Click here for entire factsheet in pdf format.

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.

Early Season

  • 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

Cultural Management

  • 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.

Chemical Management

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)