I close my windows when out scrounging this time of year so the truck doesn't fill with blackflies Lol
When I go fishing in summer, flies are a problem. Out typical flies don't bite but are annoying. But I have found that there are actually a finite number off them. I take some fly spray and after a while of buzzing around my face while fishing they eventually settle on my back. Then I sneakily grab the can of fly spray and give them a shot over my shoulder which just about kills the lot. Then no more flies. I figure that I already ingest plenty of poison so a bit more on occasion won't hurt.