Mites, Weather & Queens
I’m a beekeeper, so the majority of my posts are probably about varroa mites, the weather and queens. So many of the problems I’m likely to face are covered by these things. Varroa mites are a significant problem for honey bees, and that doesn’t look likely to change soon. The weather always has a big part to play in making a season good, bad or ugly. It influences the timings and success of forage crops, and queen mating flights. Queen bees are the mothers of their colonies; if the queens are good, the colonies are too (assuming adequate nutrition and low levels of disease).
I have now finished my annual practice of treating bee hives in winter with oxalic acid. A study at my old university (Sussex) shows that treating with vaporised oxalic acid is both effective and safe for the bees. I enjoy “vaping the bees” at this time because it’s been quite a while since I last saw my bees. It’s also an opportunity to check on the weight of the hives, just to make sure that they are not running out of stores (honey and/or stored sugar solution).
When I “vape” my hives using a sublimox device, I do it from the top. This means that I take off the roof and the cover board, add an eke made of wood which has a hole in it for the sublimox and put the roof back on upside down. Then I give them a blast of vaporised (or sublimed?) oxalic acid. The vapour tends to drift downwards and can be seen coming out of any cracks in hives, the entrance and the mesh floor if there is one. The nucleus hives just get a blast through their front door.
Two Dead Already
What I found from my brief winter liaison with my bees was:
- 2 colonies had died already (out of 29)
- the rest were all still OK for stores
- some bees were tightly clustered and ignored me
- some bees were not clustered and immediately flew up when I removed the cover board, but they didn’t sting
- the nucs, which are polystyrene, all had bees clustered rather than strolling about
Wood or Poly?
As with many things related to beekeeping, there is a broad spectrum of opinions on hive types, particularly the polystyrene vs wood debate. I have both hive types (poly and wood). There are definite differences between the two in terms of bee behaviour from what I have seen. Of course, I only have a few hives, so it’s hard to draw firm conclusions from such a small sample size. I have yet to determine which hive type is best for either me or the bees, which suggests that the difference isn’t enormous. They both seem pretty good.
My bees are in Cheshire where the weather is quite mild. We sometimes have temperatures below freezing, but nothing like what beekeepers in some other areas experience. My understanding is that poly hives originated from somewhere much colder (Scandinavia?). Still, many have adopted them in the UK and Europe with very positive results. I insulate the roof of my wood hives so that any condensation forming inside will be on the walls, not the ceiling.
When I popped open my hives to treat them recently, the bees in the wooden hives were all in their cluster at 6 to 10 deg Celsius. In the poly boxes, they were much “looser” and moving around in the hive, so presumably, the poly hives were warmer. That makes sense. I don’t know if it’s good or bad that bees are not clustered in winter. I do know that whatever goes on in there, my bees in both types do fine.
Queen Selection for Breeding
I suspect that the bees that come out of winter well in the wooden hives are more likely to have the wintering qualities I’d like in a breeder queen. Let’s face it if any of my bees swarm they will end up in another beekeeper’s hive, which is probably made of wood. Or they may end up in a roof or disused chimney, or even a tree. They’ll need to be tough to survive. Anyway, as I said, I have both hive types, and it’s more important that I’m an excellent beekeeper than what kind of house my bees live in.
Large Scale Honey Bee Trial
There is an excellent article in the American Bee Journal by James Masucci called “Managing Varroa Mites: Lessons Learned from Large Scale Honey Bee Field Trials.” The data in the article was collected from a field trial with over 2,000 hives lasting 22 weeks, at 11 locations throughout the USA. Some of you may believe that anything that comes out of America has no meaning for beekeepers in the UK or Europe, but if that’s you, I think you are wrong.
The main points are:
1. Establishing a mite strategy requires an understanding of the dynamics of mite populations throughout the year, how they respond to treatments, and how they affect colony health.
2. Don’t let mite levels get too high. You can never quite recover from high mite loads. Frequent monitoring is critical.
3. Treatment efficacy is optimal if mite loads are 2% or lower at the beginning of treatment. Colonies treated at 2% lived 280 days, colonies treated at 6% lived 130 days, untreated colonies lived 85 days. This highlights the need for monitoring mite loads.
4. Virus levels persist long after mite levels are reduced.
5. Mite effects vary by location and even by colony. What’s happening in the next town or next door may not reflect what is happening in your hives.
6. Mite treatments don’t always work, and one lousy colony can spoil the whole apiary. Monitoring before and after treatment is needed.
7. A mite management program is critical to maintaining healthy hives, and the system needs to be tailored to your locale and to your bees.
8. When mite levels get out of control, the possibility of spreading mites is real, and miticide efficacy decreases.
If beekeepers could understand and follow these points, we could make a real difference in bee health everywhere.