Alcohol Wash for Varroa Mite Counts

Spring is in full swing and it’s time for making babies. Baby bunnies, baby birds, baby bees……and baby varroa mites. As your colonies expand, so does their resident mite population. At this point in the year the bees are still outpacing the mites, but once summer hits the mites begin to take over. I want to know what is going on regarding mites in my hives, so I decided it’s time for the first mite count of 2016.

There are several ways to check your mite levels, and I chose to use the alcohol wash method as detailed by Randy Oliver atĀ Scientific Beekeeping. It is the most accurate method of discerning the level of mite infestation, but it does sacrifice the bees used in the count. If this bothers you, try using powdered sugar for the shake instead. It’s not as accurate, but the bees will survive.

I had the best intentions of making a shake jar I could use out in the yard while I’m working the hives, but it’s still on my to do list. Since managing mites is not something that should be put off, I grabbed my sample of bees in pint mason jars and brought them home instead.

Half a pint is one cup, or approximately 300 bees. I will take the number of mites that I get from the alcohol wash and divide it by three to get the number of mites per 100 bees. Example: 9 mites/3= 3 mites per 100 bees or a 3% infestation.

Along with your jar of bees, you’ll need rubbing alcohol and a screen that is large enough to let mites fall through, but keep your bees in the jar. Fill the jar with enough alcohol to cover the bees and then shake the crap out of it.

After shaking I placed the screen over a bowl and poured the bees through it. Because this is my first time doing an alcohol wash (and because I’m more than a little OCD with new projects) I also dumped the bees out on a paper towel and went over them one by one. Seriously. I also pinch pennies until they scream, so I reused the same alcohol for all four samples.

I was afraid I was doing it wrong since I wasn’t finding any mites! In my fourth sample I finally found 2 mites total. The hive with mites has been slower to build up this spring, and also has a queen from a different genetic line than my three mite free samples.

I will monitor for mites again next month, and treat with oxalic acid vaporization (3 times a week apart) or formic acid pads if my infestation percent rises over 3%.

As a side note, I had not bred any new queens from the hive with mites because I was unimpressed with their overwintering strength and they make excessive propolis. I’ll continue to monitor, but the mite count supports my decision at this time.