Spotted Wing Drosophila (SWD) update August 26, 2016

By Pam Fisher, Fruit Crop Specialist, Ontario Ministry of Agriculture, Food and Rural Affairs, Simcoe Resource Centre

The spotted wing drosophila monitoring program has now ended and traps have been removed from most sites. Thanks to Erin Hanna – OBGA- for coordinating the project and to Christine Wyville- OMAFRA –for processing the samples from each site – she counted thousands of flies! Thanks also to growers, OMAFRA scouts, and other volunteers – including scouts from N.M Bartlett, and consultants Lindsay Pink, Margaret Appleby and Kevin Schooley who collected traps and sent in samples each week. We really appreciate the help of all these volunteers.

SWD populations continue to be very high and damage is easy to find now in all berry crops. A combination of control strategies is necessary to keep damage from this pest to a minimum. These include frequent thorough harvest, immediate postharvest cooling, and weekly insecticides with very good spray coverage. Even this is not enough for blueberry growers at this time of the year, many have stopped harvest now. I estimate 10-20% of the blueberry crop has been left behind. What are your estimates?

Day-neutral strawberries and fall-bearing raspberry crops are also under high pressure from SWD. It is important to re-apply insecticides after a heavy rain ( ½ -1 inch or more). If you run into problems with SWD, strip all ripe fruit off the plant, spray and start again. We are interested in documenting crop losses from this pest, so let me know!

Recent research is suggesting that landscape fabric (black weed mat) may help reduce pressure from SWD. Fallen fruit essentially cook on the landscape fabric, and/or larvae fail to develop into pupae because they can’t hunker down in the soil surface.

Here are the products registered on 2016 for SWD. Remember MAKO is not registered on blueberries. http://www.omafra.gov.on.ca/english/crops/facts/swd-registrations.pdf