How Often Should I Test for Varroa Mites?
Ask the Expert!
William Chappell asks:
Hi. I live in the Puget Sound region of the Pacific Northwest. I would like to know when I should start testing for varroa mites. And then what schedule should I follow for the following months? I will be using the alcohol wash method. Thank you!
Rusty Burlew replies:
Not long ago, I tested and treated for varroa once a year in August. That schedule worked successfully for many years, but things are different now. Since so many people keep honey bees, the mites are everywhere and reinfestation can happen daily.
It’s hard to recommend a schedule because the rate of reinfestation will vary depending on the number of hives — both managed and feral — in your immediate area. By immediate area, I mean a 5-mile radius, about 50,000 acres.
I now test (and usually end up treating) four times a year, although I know people who now do it monthly. It comes down to what you find in the hive and what your treatment threshold is. Some like to treat when they find one mite per 100 bees, others like to wait for 2 or 3 per hundred.
In short, I think every three months, beginning when you first receive your bees, is a good place to start. Lots of folks like to treat the packages before installation, whereas some wait until the colony is settled in and the queen is laying.
The treatments are hard on bees, so it makes sense to test before you treat so you don’t end up medicating bees that don’t need it. But equally important is testing after treating to determine if it was effective. You can’t assume a treatment worked: you must verify.
Mitekeeping will keep you busy because the mites just keep coming. Colonies pick them up at flowers, when robbers stop by, or when bees drift from hive to hive. Some keepers estimate that up to 20% of bees go home to a different hive at night. This varies with hive density, but it’s a staggering number, especially if untreated colonies are in the area. You simply cannot stop the influx of new mites.
My advice is to start with a three-month testing schedule and study your results. Lengthen or shorten the time according to the results until you find a schedule that works for you.