Varroa destructor: one of the worst bee enemies

Varroa destructor. Have you ever heard about it? At the different beekeeping webinars I have attended so far, I heard often speaking about it. From the not-so-pleasant name and the tone they used to talk about it, I could understand that, well, it didn’t sound that good. What is it exactly? It’s an acarus, one among the worst threats for our friends bees. But what does it do? Where does it come up? Was it always there? Can we do anything to limit its effects? You may wonder this and much more. Let’s see from closer the acarus varroa!

Does the acarus Varroa exist since always?

The answer is …no, at least not in our regions! Indeed, it comes from pretty far away, more precisely from Asia, specifically from Indonesia. As explained in one of the beekeeping manuals I have read so far, there it was existing since so long that a kind of balance between the parasite and its host was created. Let’s say, it was nothing so nice, but neither anything too serious. Then, during the second half of the XX century, it appeared in Europe. In Italy approx. in the eighties. You are wondering you too, how the hell did it reach us??? Most probably this all happened due to trading exchanges of hives and beekeeping tools, without the proper cautions and requested health certifications. So so, someone did not follow the rules and imported varroa to Europe. Compliments! You may think “ok, but if it was nothing so serious there, why should it be here? We’re always speaking about bees”. Unfortunately it’s not this way, because bees from the Indonesian archipelago have been living with this parasite for about 70 million of years, hence, they had enough time to reach a peaceful coexistence. Nevertheless, all the bees outside that area absolutely no. For this reason, the effects were and still are totally devastating.

Let me better understand: what does it do?

It’s a tiny acarus (its dimension? A millimeter), but it can cause big damages! It can affect both brood and adult bees. From drones to worker bees. Looking at it through a microscope, it seems a little brown octopus. With its tiny ‘tentacles’, it grabs on to the bee and eats its blood. Further it’s well explained in another book I read: as any parasite, its victim is its new source of food, but it also reproduce. How? It enters the brood cells and after a couple of days it lays eggs (one per day more or less!). In this way, it increases more and more.

What are the Varroa effects on bees?

Varroa eats the blood of the bees, by drilling their membranes. This causes weakness and wounds. Would you believe that this is the less worst part? Yes, because unfortunately there is also an indirect bad effect. While eating, Varroa injects in its host some very dangerous virus, such as the DWV (Deformed Wings Virus). Bees are strong, but Varroa eats through a wound that is always open. Therefore, bees’ immune system is focused on this last one and in the meanwhile the virus injected by Varroa acts without being bothered, reproducing more and more till gradually killing the super organism.

Is there any way to prevent Varroa?

fighting against Varroa
Granpa Heinz taking care of the yearly Varroa treatment

Consider that 99 out 100 hives of any beekeeper nowadays has Varroa. What we can do is trying to coexist with it, keeping it under control and taking care with some treatments so as to limit its negative effects. Do you remember when we spoke about the structure of a hive? We mentioned the anti-varroa tray! When we carry out inspections, from time to time we have a look at the anti-varroa tray as well. In these occasions, you can see if there is any varroa and especially how much it is. From there, we can understand how the hive is. Then we clean the tray, we put it back and during the following inspection we can see whether the situation has improved or not. Among the different Varroa treatments, what granpa Heinz has been using since always is formic acid, generally at the end of Summer-beginning of Autumn. It’s a organic acid (to be handled carefully, as granpa Heinz highlighted more times when explaining to me). At a empty frame, without any honeycomb (one per each hive), we put a little box with formic acid in (quantity? still not clear honestly, granpa Heinz takes care of this without measuring precisely, like any person that has been doing something since a life).

Near this there is a small piece of carton, whose bottom side is soaked in this acid and we’ll ‘spread’ it in the whole hive. It has an advantage: it manages to pass through the cells’ operculum, where we told that the acarus gets its nest and reproduce. It’s not harmful for the bees, but it affects Varroa, by decreasing its number in the end.


I do love sharing with you all the things I have been learning about bees, you know. A kind of coffee break with bread, butter and awareness. What you are reading here, of course, won’t change your life. However, I can show you things from a different perspective, right? For example, something that impressed me much is that the most serious bee diseases come from mankind. They are connected somehow to man. This made me deeply sad! Mankind! Us! The last ones arrived here that, despite this, despite all what we know, we don’t care that much about the ecosystem balance. We really hope that this article too has provided you some points to ponder about. Let us know if it’s this way. For any question or doubt, we´re here! 🙂

A hug,

The Gäblini

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