Spotted Wing Drosophila in Ontario

3 spotted wing drosophila  on a raspberry fruit.Spotted wing drosophila - male (left), female (right)Ontario SWD trap 2012

Spotted wing drosophila (SWD) is an invasive vinegar fly that has the potential to cause extensive damage to many fruit crops. Surveys coordinated by OMAFRA in 2012 indicate SWD has spread to most fruit producing regions in Ontario.

Based on experiences in western North America, we expect SWD will become a chronic pest to deal with in years to come. Early detection is the key to limiting economic damage.

Ontario Monitoring Program

In 2010, the Canadian Food Inspection Agency surveyed for SWD at selected sites. The first SWD in Ontario was recorded in November, 2010 in a backyard location in Niagara region.

In 2011, OMAFRA staff worked with crop scouts and consultants to coordinate a SWD monitoring program at 60 sites in 16 counties. SWD was first captured on a commercial farm the week of August 13. Flies were trapped at 60% of sites in 12 counties by late November.

In 2012, OMAFRA staff, crop scouts, consultants and an industry-funded project coordinator worked together to place traps at 108 sites in 25 counties. First capture of SWD was June 29, 6 weeks ahead of the previous year. By August, SWD had been trapped at 90% of monitored sites, and in all counties.

In 2013, a regional monitoring program will continue, with traps at representative sites in each fruit growing region. Our SWD project is now funded thanks to the support of the Ontario Berry Growers Association and the Ontario Highbush Blueberry Growers Association, through OFIP, as well as HJ Heinz Co., Dow AgroSciences Canada, Engage Agro Corp., Bayer CropSciences Inc. and E.I. du Pont Canada Company.

Updates on SWD activity will be posted weekly at

In addition, growers are encouraged to monitor for SWD on their own farms. Monitoring includes trapping for adults, examining fruit for damage, and using salt water tests to check for larvae in fruit.

Results from Commercial Farms in 2012:

  • First field detection of SWD occurred during the week of June 18-25 in Essex County (nearly 2 months earlier than in 2011).
  • From late June to early July, SWD showed up in various counties (Kent, Oxford, Elgin, Grey, Niagara, Norfolk and Huron).
  • New positive sites and SWD numbers increased throughout July and August.
  • More than 92 sites in 26 counties were positive by late August.
  • SWD was captured at over 90% of monitored sites and in all monitored counties.
  • Most trap captures occurred after harvest.
  • SWD was found in apple cider vinegar traps located near raspberries, blackberries, blueberries, strawberries, cherries, peaches, apricots, grapes, currants, goji berries, sea-buckthorn, elderberries, plums, kiwi ,tomatoes and wild hosts.
  • SWD adults were reared from healthy fruit on commercial farms and wild hosts including brambles, dogwood, pin cherry, pokeweed, buckthorn, elderberry and nightshade.
  • Infested fruit and crop losses were reported in some berry crops.
  • SWD were trapped at some locations as late as January 2013.

For more information:
Toll Free: 1-877-424-1300
Author: OMAFRA Staff
Creation Date: 8 June 2011
Last Reviewed: 29 August2013