Spotted Wing Drosophila Update, July 25-Aug 1, 2019

This post contains a summary of trap counts for July 25-Aug 1, 2019.  The numbers reported are number of SWD per trap.

The regional monitoring program is being conducted in berry and stone fruit crops and grapes in Essex, Chatham-Kent, Elgin, Norfolk, Niagara, Durham, Ottawa/Carleton and Northumberland counties.

The monitoring project is supported by a grant from the Canada Adaptation Program and collaboration among Niagara Peninsula Fruit and Vegetable Growers Association, Ontario Tender Fruit Growers, Eastern Ontario Berry Growers, Grape Growers of Ontario, OMAFRA staff and private consultants.

Traps were first deployed in berry and stone fruit blocks.  We have placed 4 traps with commercial SWD lures at each site.  As crops are harvested, traps are “RETIRED” and monitoring discontinued.

Use these results in addition to your own monitoring program to determine when SWD is present on your farm.  Conduct a salt water test or a plastic baggie test to confirm presence of larvae in fruit.  Click here for instructions on doing this test.

SWD has been identified in all monitored areas and counts have continued to increase.  A similar monitoring program in Michigan is also reporting increasing SWD pressure:  https://www.canr.msu.edu/news/michigan-spotted-wing-drosophila-update-july-30-2019

Once sustained catch occurs (two weeks in a row with SWD) growers with ripening crops susceptible to SWD should consider using a product with activity against SWD in preharvest sprays.  Check the SWD product registrations on our website.

According to David Jones, MSU extension, “For plums and peaches, you shouldn’t be starting management the moment that color creeps in,” he said. “If you initiate a spray program around 4 to 5 pounds of firmness, you should be able to catch them.”  Source:  https://www.goodfruit.com/new-mindset-for-managing-spotted-wing-depredation/  Our preliminary trial on apricot last year supported this observation.  We are currently testing susceptibility of apricots and plums to damage by SWD.  Fruit collected at pre-commercial ripeness, commercial ripeness and tree ripe are being exposed to SWD under lab conditions.  Fruit firmness is measured to classify into the 3 ripeness classes.  Fruit are exposed to SWD for 24 hours and then incubated to allow any SWD to mature to adults.  This will be continued with different plums and apricots as they ripen and into peaches and grapes.

This project was funded in part through the Canadian Agricultural Partnership (the Partnership), a federal-provincial-territorial initiative. The Agricultural Adaptation Council assists in the delivery of the Partnership in Ontario.