Spotted wing Drosophila (SWD) populations usually start to soar in late-July, after the majority of the tart cherry crop is harvested. In 2017, numbers rose quickly, reaching levels much higher than normal by the time cherries started to colour. This resulted in massive crop losses due to severe infestation of cherries.
We have been monitoring spotted wing drosophila across Ontario since late May.
We have switched from apple cider vinegar to commercial lures as shown in the image below. Traps were established in berry crops and nearby cherry orchards. Consultants and OMAFRA staff have been sending samples in for counts. As of June 20, one fly had been found in one tart cherry orchard. We are expanding our trapping this week into more cherry orchards as they start to turn colour.
The flies are attracted to fruit as it starts to lose its green ground colour and continue to be attracted to them through harvest. SWD eggs are laid under the skin of ripening fruit. The larvae that hatch from the eggs then feed within the fruit.
The click on the link below for the table showing the products that are registered for SWD in cherries and their relative activity vs both SWD and cherry fruit fly. If a product is not listed, it may have activity against cherry fruit fly but not SWD. A higher number for relative activity indicates a more effective product. It is recommended that you rotate among modes of action for both pests to minimize the risk of resistance development.