It is very important for growers to monitor for spotted wing drosophila (SWD) on their own farm to determine when it is necessary to begin a spray program. Once SWD is identified and ripe fruit is present it is time to spray. Monitoring will help growers confirm SWD presence before the population really builds and in time to begin an effective management program. For on-farm monitoring growers need practical, effective tools that are not time-consuming or labour-intensive.
A project funded by Niagara Peninsula Fruit and Vegetable Growers Association, Ontario Tender Fruit Growers, Grape Growers of Ontario and Eastern Ontario Berry Growers Association supported a research project to develop the methodology to not just identify SWD in samples but to quantify it. The molecular method allows for detection of a single SWD in a sample with 1000 non-SWD flies with 97% accuracy.
Monitoring for SWD
Set up 3-4 liquid-based traps in shaded areas around the field to monitor SWD. Set up the traps when fruit start to turn colour and continue until SWD has been identified. Each trap should be baited and have 100 mL of mouthwash. These traps should be collected every week and the contents sent to the Agriculture and Food Laboratory, University of Guelph. The contents of multiple traps can be combined into a single sample for testing. Commercial traps and lures can be purchased from several suppliers, listed below. In comparison trials, Scentry lures have given the best results. If you prefer, you can make your own traps but make sure there’s a way to suspend the lure above the collection medium. Mouthwash (instead of plain water or apple cider vinegar) proved a much superior collection medium in the traps as it effectively preserved samples and reduced contamination that interferes with the test.
The price for testing is $80 per sample for 10 or more samples submitted as a batch. For batches of less than 10 samples, a setup fee of $100 will apply. The turnaround time from sample receipt to reporting results will be 2-3 business days. Ensure that shipping containers are leak-proof and ship by courier to avoid delays. The submission form can be found at: https://afl.uoguelph.ca/sites/default/files/pdf/general-submission-form.pdf
Trap and lure suppliers:
Alpha Scents, Inc.
West Linn, OR
Great Lakes IPM Inc.
Scentry Biologicals Inc.