Beekeeper-supported Research Update
by Randy Oliver
Since alcohol is in short supply, I've been asked by many beekeepers what they can use for monitoring varroa. Although my current series on mite washing will be getting to my testing of various liquids, allow me to give a brief preview of one of my findings.
Dawn Ultra detergent (to date I have data using the clear "Lemon essence" product) works very well for mite washes, on par with 91% isopropyl, better than 70% isopropyl, and much better than 0°F windshield fluid. Disclaimer: I have no connection with, or interest in, the manufacturer of Dawn dishwashing liquid.
Dilute to 1-2 Tbl per gallon of water. A weaker solution is less efficacious, and there is no benefit to making it stronger.
Allow the bees to soak in the solution for a full minute before agitation, by which time most of the mites will have dropped to the bottom of their own accord.
Final agitation should be a swirl action, with no up and down shaking. Little agitation is required for basic mite monitoring (as opposed to hard data collection).
For counting after agitation, a wonderful trick that I've found is to make a stand to hold the mite wash cup 4 inches above the face of a 6-inch diameter, 10x magnifying mirror (makeup mirror) placed horizontally below the cup. 10x is the best magnification, and 6" dia the best size. Looking down, this gives you a greatly enlarged view of the mites (you can see their legs) and makes counting a piece of cake.
Viewing from the bottom up means that the foam from the detergent is not a problem.
Warning: A magnifying mirror, casually placed, can easily start a fire should the sun hit it. The focus point is a few inches from the mirror, and sunlight through a truck window is enough to start a fire within seconds (practical experience).
ALWAYS place the mirror into an opaque holder when not in use.