After 4 years of monitoring for Spotted Wing Drosophila (SWD) at 50-100 sites each year in Ontario, we think this pest is here to stay. Every year we capture the first SWD flies in late June or early July, around the end of June strawberry harvest and the time of summer raspberry harvest. Every year the trap captures quickly escalate, with SWD pressure being extremely high during blueberry and fall raspberry harvest. We have consistently found damage in all the berry crops except early strawberries, and suspect cherries have been damaged as well. Our message to growers is to protect susceptible soft fruit crops if they are ripening when SWD flies are active.
However, we have noticed that trap captures on individual farms do not predict the potential for crop damage on that same farm. We sometimes find damage before SWD are caught in traps at that site. We think it is more useful to consider trap captures in an area, rather than an individual farm. We also think that growers should focus their efforts on recognizing the first signs of damage to fruit. Immersing fruit in salt water to float out SWD larvae is also a good tool for growers to assess their SWD management programs.
To support berry growers in their management of SWD, the Ontario Berry Growers Association(OBGA) and OMAFRA have teamed up to run a regional SWD monitoring program in 2015. The project will be coordinated by Erin Hanna, who works for the OBGA. Traps will be placed at approx. 30 representative sites across the province, from Harrow to Georgian Bay to Ottawa. Volunteers from agribusiness, private consultants and OMAFRA students will pick up the traps and send them to Vineland, where OMAFRA students will process the trap contents. Weekly reports on SWD activity will be sent to berry growers through the Berry Bulletin, and available to all growers on ONfruit@wordpress.com as well as in Hort Matters.