When trapping for SWD there are a few important points you should keep in mind.
1) Check the traps weekly or more often if possible.
2) Replace the Apple Cider Vinegar each week. (fill the cups at least 1/3 full, the vinegar will evaporate)
3) Some people take the used vinegar off site to dump it, this is probably the least risky approach. Do not dump it on blueberry plants, it is acetic acid and it will defoliate plants!!
4) Place one trap in the shade on the edge of a field (It does not need to be in the field)
5) Place a trap near wild raspberry or blackberry patches on the edge of fields
6) Plastic lids likely need to be replaced on a weekly basis as they become brittle in the sun. Saran wrap and an elastic might work (don't cover the holes)
Monitoring in your fields is the best way to determine when or if you need to spray your fields.
As of today, Wednesday July 31st, I have no reports of SWD found in any wild blueberry fields in Nova Scotia.