Article by Dr Kirsten Traynor, Flickerwood Apiary, Maryland, USA.
In the spring, you can use the biology of the bee against the biology of the mite. Mites prefer drone brood. Just through intensive drone brood cutting 4-6x per season, you can eliminate 75% of the mite population compared to controls.
I speak to a lot of beekeepers about varroa control. Since 2001 I have run an organic apiary. For many years I was able to control my varroa in my colonies through intensive drone comb cutting and winter oxalic acid dribble treatments. In the last few years, drone comb cutting alone has not been enough, but it does help to significantly reduce mite numbers in colonies. A 2003 Bee World paper shows up to a 75% reduction in mite population via drone comb cutting compared to controls.
When I say drone comb cutting, I don’t mean the little bit of drone comb bees draw on the edges of comb or in-between boxes. Rather I mean full frames of drone comb. Like many, I invested in those green plastic drone combs when they first came out. And they are a royal pain. You need to pull them out, freeze them, then put them back in the colonies for the bees to clean out. It’s messy and you’re making the bees clean up your mess.
There is an easier, cheaper, more sustainable way. I use all mediums in my operation. So I simply use an empty medium frame with no foundation and place it on the edge of the brood nest right before the pollen bound frame, which I call the pollen wall. I use one per brood box, two per strong colony. When I was running deeps, I used one full deep in the main brood box or you could use two shallows in each brood box.
I label the frame drone on the topbar of the frame in big letters, so I can find it easily. I mark my calendar, so that I know to pull it in 3 weeks. Drones take 24 days from egg to emergence, so in 3 weeks none of those guys have escaped from their cells. It even gives me a few days of rainy weather wiggle room.
We give our bees no place to put drones, so they almost always draw perfect drone comb for me. The only time they draw worker brood instead is when the colony is headed by a newly mated queen. I cut out these drone frames every 3 weeks and put the empty frame right back in. Very simple.Takes all of 30 seconds to do. Works as a varroa mite magnet to suck mites out of your hive without chemicals.
Is it enough by itself? Definitely not. Does it give you a leg up in the race to control varroa during the season? Most definitely. How long do I do this? I keep putting the drone frames back in and cutting them out until the colony stops drawing drones; usually in July or August.
Cut the drone comb out by simply running the hive tool along the edge of the inside frame. Often gravity alone will do the trick, as drone brood is heavy.