A strategy for varroa treatments

Let’s get something out of the way from the very beginning: Yes, varroa is the largest threat to honey bee health. But that doesn’t mean that you’re helpless. It can be managed efficiently, but that needs knowledge and good practices. Thus, some effort. A strategy for varroa treatments, a plan. “But that doesn’t work under my conditions!”, I hear you cry. Yes, it does. It may be necessary to adapt a few things, but varroa can be managed. Full stop.

Mostly, these comments come from a point of insecurity. Maybe also fear. It’s difficult to change habits, to do things differently. Especially if, like in Australia since last year, the situation changes abruptly. The last fortress against varroa fell: it was introduced by the port of Newcastle to New South Wales. The authorities first tried to eradicate the mite, as they had done with success at earlier occasions.

Already one or two months after the introduction, it was clear to me that this strategy wasn’t right. I explained why in this video. Which brought me some criticism, I was accused of not being helpful. Again: I know that new situations can be scary and daunting. Especially, if beekeeping is your job, if your family depends on it. But what is the right reaction: panicking or learn from those who already know how to deal with the issue? Now, fortunately in my opinion, the approach in Australia changed to management.

Australia can profit from 50 years of experience

Let me tell you something not so nice: You’re not special. In the sense that you’re not alone with this situation. Here in Europe, we’re dealing with it since the 1980s and beekeeping is still going strongly. It was one of the few industries that still grew throughout the economic crisis in the late 2000s. You’ll have to change a few things, and learn a lot. Take the responsibility. But then, you’ll be fine. Managing varroa is based on biology, the parasites’ and the hosts’. That’s the same in Australia, Europe, or Africa.  

A disclaimer in between

That said: If you have any mental health issues that got triggered by the situation, please use the assistance offered by the Department of Primary Industries (DPI). Just scroll down on the linked site and you’ll find resources. This is a very stressful situation, but you’ll be able to manage it with the right help.

Dealing with a new situation

I’m not a mental health professional, obviously. But I know something about varroa. I can help with that. From the almost 50 years with varroa in Europe, I experienced 25. When varroa mites arrived in Europe, it was quite devastating. There were massive colony losses because of the mite, beekeepers bursting into tears at the association meetings after losing everything. So, treatments had to be found, and quick. The first step was to use known acaricides, i.e. products that were used against mite infestations in agriculture or for other animal species. This wasn’t always positive, what kills mites, potentially also kills bees. In addition, there were residues both in the wax and the honey. We still find some of these substances in some wax samples.

Australia doesn’t have to make all these experiences by itself. There are good and efficient treatments out there. The DPI lists them all in their resources. Now, it’s your turn. Learn how to use them correctly. To keep your colonies healthy, but also the products safe for the consumer and the environment clean. This is still your responsibility, as it was before. In my opinion, varroa also forces beekeepers to think about and improve their practices. It would be better if this wasn’t necessary, but now the situation is as it is.

How varroa treatment concepts were born

When I began my PhD in 1998, one of the first things I experienced was a meeting of the European Group for Integrated Varroa Control. As a “small” PhD student, I was pretty impressed by this group of researchers. They were speaking about things I hardly understood in those days, coming from a different area of bee research. But it was in this group where most of the treatments of “natural origin” were developed. Formic acid, thymol, oxalic acid – these substances were tested not only for their efficacy, but also for their safety for bees and the right posology – i.e. how to use them and when. This time is also the origin of the first strategies for varroa treatments. Things like:

• How often do we treat?
• When do we treat?
• What dosages do we need for different colony sizes?
• And not less important: what standards do we need to develop further treatments?

Coming last as a chance

As a young researcher, I had this great fortune of being received by the European varroa group as one of them. It was then when I learned the high value of cooperation. I had mentors that became close friends. Obviously, there was more work done also in other parts of the world, but this group broke the ground, gave the foundation for everything that came afterwards. It’s a strong foundation also Australian beekeepers can build on.

This is what I mean when I say you’re not special. You can learn from others because the biological, pharmacological, and practical things are already there for you to learn. In addition, you may avoid some mistakes that other regions of the world made. Fortunately, you even get assistance to deal with the stress this situation means. In the 1980s nobody even thought that this could be necessary. So, all this to say: You’ll learn to deal with the situation. You’ll have to adjust and put effort in it. Which may be a pain. But that’s life.

The biology behind a strategy for varroa treatments…

So, let me give you some rules of thumb to deal with varroa mites. You have a list of different products that you can use. Every single one with special characteristics. First and foremost, you have to always keep in mind that these products are veterinary medicine. So, “the more, the better” isn’t the right strategy. A better motto: As much as needed, as little as possible.

The bees…

Here’s where biology comes in: Honey bee colonies change over the year, depending on the climatic conditions they live in. They’re sometimes stronger, sometimes weaker. This also depends on the flowers they have available to feed on. In times of little pollen and nectar, the colonies will be weaker, have less brood. This time often is a bottleneck to colony survival. In temperate regions, this occurs in winter. In Mediterranean climate, it may be a very hot and dry summer. In subtropical and tropical regions, this colony development may be less marked, but still there. The important thing here: worker bees that live during these periods of low resources live longer than those in fully active colonies.

… and the mites

Varroa mites, on the other hand, have a different dynamics: In presence of brood, their population will double every month. Why? Because they reproduce in the capped brood cells. So, the more brood, the more they reproduce. The number of varroa mites follows the number of bees and brood cells, with some delay. When the colonies become weaker, they may still increase in number in the remaining brood – and become more mites than bees in the colony.

… and how to apply the biology to practice

The treatments depend on this dynamics. There are two crucial points at which we need to get the varroa infestation down:

1. When the longer lived workers grow up that will keep the colony going in those times with lower resources.
2. Before major honey flows/pollination jobs, when we want the colonies to be productive and strong.

You will read “spring” or “summer” treatment for the first one, and “fall” or “winter treatment” for the second one. But this applies to cool temperate climate and can be confusing if you live under other conditions. You will read this too in the table below. But now you know what I mean by that.

So, as rule of thumb: Two treatments are enough to maintain healthy colonies. The timing depends on the colony and infestation development. Think of when your colonies are weakest – treat BEFORE this period. Then, think of the most productive period of your colonies. Again, treat BEFORE this time.

By this, you protect the bees during their survival bottleneck and make sure that your colonies do their job when you need them to.

Think in active ingredients, not in products

Every drug – and varroa treatments are just that – has an active ingredient or active substance. Both terms are synonymous: It’s the substance that will kill the varroa mites. It may come in different forms, the “formulation”, like strips, gel, solutions, etc. There may be different products with the same active ingredient. Knowing some basics about their properties will help you to choose the right product. Here’s a little overview:

I already have some more detailed resources on oxalic acid and thymol, as well as why the EU didn’t register Hopguard. Repeating all of that here would be a little bit too much. The other active substances will follow. And there’s also a post explaining why varroa treatments are veterinary medicine and not a miracle cure – recommended if you want to build some resilience against the scam that will now appear also in Australia.

Finally, to develop the right strategy for varroa treatments in your practice, you may have to adapt a few things. Your practice will change and adapt over time. That’s totally normal. The characteristics of the active ingredients stay the same independently of the conditions you work in. But a certain substance may not be right for your requirements. This is why you need to learn the basics now. Insisting on “I’ve always done it like this” in changing conditions is much worse than varroa. When you continue to learn, then you’ll make it through this and the challenges that will come up in the future. Because they will.

If all of this seems overwhelming and you need some help there are several ways how to get this.

1. Subscribe to the Bee Health Letters – on the homepage, just scroll down until you get to “Keep current with BeeSafe”. Once or twice a month, you’ll get bee health news.
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