Spotted Wing Drosophila Update August 7-14

This post contains a summary of trap counts for Aug 7-14, 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, 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.  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.

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.

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 into peaches and grapes.  According to David Jones, MSU extension expert, “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.

Some research from Pennsylvania suggests that SWD may cause issues in grapes.  See this post from 2018 for more information.  We will be looking into this as grapes go into veraison and maturity in the next month or so.

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.