Beekeepers in Vermont should be monitoring their hives for ALL diseases and pests. The Honey Bee Health Coalition has excellent information about how to check mite levels in your hives.
As VBA Secretary & Certified Beekeeper Fred Putnam said at this evening's online seminar on honey bee health, "Bees in dying colonies also "migrate" to hives at least 1/2 mile away carrying their mite and disease loads with them to healthy colonies and the native bee population." Which is a good reason for all of us to test our hives.
Randy Oliver covered this alternative to alcohol wash in the New York State Bee Wellness webinar last Wednesday night (6/17/2020.) He didn't compare this to -20F windshield washer fluid. He used 0F. But still, this is an option if you don't have alcohol. BTW, he also said that 50% isopropyl rubbing alcohol does not do a good job of dislodging mites. 70% and 91% isopropyl work much better. So check the isopropyl concentration before you buy it.