I am often asked on how I manage varroa mites, because beekeepers want to find the ‘best’ way to deal with them. My main philosophy with varroa is to do whatever you can to keep their population low, and make sure that the hives are free from this deadly parasite before your winter bees are made. If you live in a remote area, that may not be that much work. If you live in an area with higher disease pressure, then you may have to break out all the tools. On this page I’ve outlined a few example strategies that you could plan to do - and then adjust based on your bees and your monitoring.

What I plan to do in 2022

In 2022 I am returning from Sweden to about 30 hives that were cared for by friends and family. Here is my plan to manage varroa in those hives (check back in October, and see what actually happened). One thing that is different for me from a lot of other beekeepers is that I have hives for multiple reasons - some I raise queens from, some to make honey, and some to make drones for the queens.

1) Early April

Add a frame to the outside of the brood nest for later drone brood removal. We used a lot of drone broood removal in Sweden (where varroa aren’t that bad to begin with), and I think that it is useful, especially in early spring. The more mites that you can remove at this time, the slower the growth curve. Remember, our goal is to prevent the mite population from taking off before winter, so anything I can do to reducing the starting population is useful. Where I live in Michigan, we usually get a warm up in Mid-April, but it will get cold again after. So I need to make sure my bees have room for incoming food, but I don’t like to make splits or arrange the brood nest at that time. All I do in mid-April is ensure they have room by adding a box of drawn comb on top of the hive. I use deeps usually, so I will replace one deep frame from the outside of the brood nest (not moving existing brood) with a medium frame before I add this extra box. Hopefully the bees do something like the photo on the left - raising drone brood on the bottom of this frame. I’ve used this method before, and it doesn’t require new or plastic equipment, and the brood is super easy to scrape off into a bucket. I’ll mark the top of the frame so I can easily see it. If you use all medium frames, you can do the same thing with a foundationless frame.

End of April / Begining of May

I’ll start to make splits when I see signs that my colonies are ready to be split. Usually this is around the first week of May for me, but has ranged anywhere from the last week of April to after May 12th. I will make splits by removing the brood to new colonies that will get a queen cell - old queens stay in the old location with very little brood left. I’ll remove drone brood at this time as well.

End of June/ Beginning of July

At this time of year I will have a sense of what colonies will be honey producers through the end of the year, which ones are potential queen producers for next year, and which ones will get broken down into nucs. I’ll start to monitor here, because I know from past experience that colonies that have even a few mites (1-2%) by this time of year will not make it to winter with out a mite explosion if I don’t intervene. If I start to see mites, which unfortunately I often do, I will use a formic acid treatment. I am fortunate enough that I live in a place where our summers are within the safe /labeled range of formic, so I can generally find a window. I prefer formic because it is orgainc, natural, does not build up in wax, and is safe to use when honey supers are on. I will not treat colonies that have potential breeder queens, and if I’m on the fence I may not treat colonies that are smaller / going to get split again in to nucs.

Early July - Early August

Here is where I make my second round of splits out of many of my hives. You can read more about that process here. Basically I’ll leave a few hives alone that will be honey producers for later flows and will be potentail queen breeders for next year. All of the free loaders/ under producers etc will get broken down into nucs, and given queen cells. This gives these colonies a second clean break in the brood cycle. You could easily do an oxalic-acid treatment when the colonies are broodless as well, but I usually don’t, because I also teach a class at this time and I don’t have time to organize it/ get out on the right date.

Beginning of August

This is when I start to worry for the big colonies that don’t get split. I will monitor a lot at this time, because I want to make sure that my colonies are in perfect shape before the winter bees are made. Colonies that are at risk (around 3%) will get formic acid (paying attention to the timing of the earlier treatment if there was one). My concern at this time is still what is building up inside my colonies, and I want to make sure my beautiful winter bees have huge, undamaged fat bodies.

August - September

I have done my part to make sure my bees are not making lots of mites, but I can’t control what the bees in my area are doing. This time of year we can get robbing, so my bees are at risk from what is in the area. I’ll keep monitoring. Some years I don’t have a problem, some years I have a little problem, and some years I have had a big problem. On the years where there is a big problem, I have used Api-guard, which stays in the hive for a few weeks. The thought is that it would be in the hive consistently during the robbing / drifting system.

New for 2022 - I am also going to be adding robbing screens. I haven’t used them a lot in the past, but they seem like such a nice way to reduce risk of all diseases.

October

Depending on the shape of my hives and the amount of brood in the fall, and the amount of monitoring, I will use oxalic acid (dribble method). I usually don’t use oxalic because of time, not needing to, but I think it is a useful tool for reducing the mites that will be the founder population for 2023.

That sounds like a lot of work, and I don’t want to have 100 hives like you - What should I do?

I understand that there are people who have lives outside of bees, and may not want to be making constant splits, selling nucs, and growing the number of hives. If you have just a few hives, you will have to use a different timeline, because I do feel like I get a lot of control from breaking the brood cycle. Here is what you could do:

1. Make splits in spring, letting the bees requeen or using a queen cell

2. Do drone brood removal a few times in the spring - early summer

3. Plan on a summer treatment of formic acid if your colonies don’t swarm/ requeen and get a second break

4. Start monitoring very closely in early August. Note - remember that the growth curve is exponential - it will shoot up at some point. For me in southern Michigan, it often happens mid-August (but varies based on weather). If you see low levels in early August, don’t think that your work is done.

5. Do a late summer/ early fall treatment with formic (if honey is on), or a thymol treatment if honey is off.

6. Use oxalic acid once the colony is broodless.

You know, for someone who talks about “Towards Treatment Free” a lot, you just recommended a lot of treatments!

I really want to be treatment free. I really want all my friends and all the beekeepers in the world to be treatment free. I also want to stop the huge numbers of bee deaths due to this parasite. I think that if you are a queen producer you have an obligation to find bees that can live with varroa. However, if you are just a beekeeper, not working on breeding or stock selection, the BEST thing you can do to help is to keep the bees you have healthy and to stop the spread of disease. If you have a year where your bees are not managing varroa well, and you find yourself treating a lot to keep varroa populations low, then treat, and re-queen with a new queen who may have better genetics. Don’t just let the colony die and add to the problem. It is a lot of work, but we can all get to a better place together!