Tag Archives: Varroa destructor

New Varroa Treatment

Okay I don’t know if it is actually new, the method is so simple that I can’t imagine that no one has ever used this before. There was an article in the monthly magazine given out by the Dutch national beekeepers association about this Varroa treatment and I had not yet heard of it, it sounds quite intuitive.

In this treatment you would wait till after the last honey harvest so this time table is dependent on when you finished that. Starting too late will perhaps impact the rearing of winter bees. With this treatment, say in the first week of July, the queen should be caught and then trapped between two queen excluders in a honey super with at least 5 drawn frames at the bottom of the hive. Two weeks later the frames with brood should be removed and replaced with new drawn frames. A week after this, the queen excluders should be removed and a week later still you should remove the frames with closed brood along with the the honey super.

Now the idea behind this method should be quite evident and seems simple. You don’t give the varroa any other place to hide accept in the brood, trapped in the supper with the queen. By taking away the brood you, over a number of weeks, take away most if not all Varroa mites.

The only drawback of this method I see, is that this would impact the bee population quite dramatically. You would essentially be removing almost 4 weeks of new bees from the hive. The reasoning behind this method according to the article was that treatment with formic acid, which is common in the Netherlands at the end of summer, takes a hefty toll on the bees. Living in the fumes of 80% formic acid for over 3 weeks can’t be fun. I should know, I got 80% formic acid in my face once and let me tel you, that wasn’t pleasant.

So I guess all methods of treatment have drawbacks and you should go by you’re own experience. But with the number of colonies I have (uhm…one), I can’t experiment. So I guess this year I’ll be using the method I used last year which was the Apiguard variety. But this year I’ll keep a close eye on the mite drop (and look for any ants) not forgetting the Vaseline this time.


(link to article on new site: http://bees.millar-knorr.nl/beekeeping/new-varroa-treatment/)

Varroa explosion

Because of the nice weather in winter and spring the varroa populations have exploded. Winter treatment against varroa using oxalic acid is used during winter because that it is the only time that the colony is not expected to have any brood. A single treatment should impact all varroa as there should be no varroa protected inside caped brood cells.

But because of the mild weather this winter there is a good chance that the bees did have capped brood, most likely filled with varroa. And then there was the mild spring which gave the mites a head start in the bee season letting their population grow to new heights.
That is why this year the varroa treatments here in western Europe are especially important. Varroa can be a major cause in colony death over winter. More so than lack of food or extreme cold.

The local apiarists organisation in the Netherlands has published an article on the explosive varroa population growth. A beekeeper counted 4 times the varroa he would count in an average year. You can view a translation of the article by following this next link (in all honesty the translation isn’t all that good, but kind of readable).

I’m not sure how the varroa population is going in my hives. I’ll check the mite drop after the 5 weeks of apiguard treatment tomorrow and update this post accordingly (if the weather allows, lot of rain here lately).

Talk to you soon,

Deformed wing virus

Deformed Wing virus
Deformed Wing virus

Siting in front of my hive one day, the hive at my parents house, I saw a bee stumble out of the hive and drop onto the ground. On the ground the bee continued to crawl on. I was surprised and concerned. I gathered up the bee to get a better look at it. There was clearly something wrong with it’s wings. It didn’t try to fly and fell to the ground when falling off of my hand. I had recently read about deformed wing virus (DWV) and that it could be an indication of a Varroa destructor infection as an opportunistic pathogen. After reading some more I was quit sure this was DWV. The wings were clearly deformed, not as bad as you can find on the interwebs, but you’ll see if you click on the image on the left it’s bad enough.

It was right before the time I needed to treat the colony against varroa with formic acid so I was hoping that would take care of the problem. Other beekeepers I knew didn’t seem all that concerned so I reasoned that it wasn’t extraordinary. Still after my previous troubles, I wasn’t all that certain. Apparently the formic acid treatment was enough, I saw no more bees with DWV, the bees don’t last long after crawling out of the comb with this affliction so I guess no more bees with clear DWV were “born”.

Without Varroa the bees can handle DWV fine but Varroa makes them more susceptible to any disease. Varroa mites will often be carriers of DWV and in that way infect the bees. According to the Wikipedia article Varroa will serve as a kind of incubator for DWV and only colonies with a serious Varroa infestation suffer from it. I can only hope that the bees are relatively free of Varroa now and will make sure to treat them against Varroa next year so they stay or become healthy.


Formic acid treatment

mierenzuurAugust is the time to treat the bees against Varroa infection. This mite, aptly named Varroa destructor, is one of the most serious enemies of the honey bee. It is a pest imported from the far east and has been spreading over Europe and the rest of the world for the last 40 years or so. Only Australia is free of this pest and I’m sure they hope to keep it that way.

Without treatment your colony will surely die. Most likely not of the Varroa mites them selfs but of secondary/opportunistic  infections like deformed wing virus (DWV). In the Netherlands organizations, like bijen@WUR, researches bee health and are on the lookout for causes of bee disease and research and test treatment plans. So far there is no sure way to be rid of the Varroa, all we have so far are means to keep the Varroa at bay.

One of the treatments against Varroa is drenching your bees in formic acid vapor for about 14 days. The time to do this is after you have harvested the last of the honey so at the end of July or at the beginning of August. There are other treatments but this is article is about the treatment I performed.

You can perform this treatment in a number of ways, the one I employed, which I think is the easiest and cheapest one, is by placing a clean household cloth on top of a queen excluder on the top brood box, placing an empty honey super on top and soaking the cloth in a certain amount (30 ml per brood box) of formic acid (60%). You will leave this cloth with acid in the hive for 4-5 days and repeat the procedure twice to get a treatment totaling about 14 days, to get all the mites also in closed brood.

Liebig dispencer

Perhaps an easier way but one requiring buying some gear entails buying a Liebig dispenser shown in the image below. It requires a little less effort and uses 85% formic acid in stead of 60%, which is the concentration that is readily available and so doesn’t require diluting. The dispenser is not expensive, so I guess that will be the method I will be employing in the future. I am myself the best example why not having to dilute you formic acid is an advantage. Having worked in chemical/biological labs for in total well over a year, and having instructed young students in lab practices, I didn’t think to much of working with 85% formic acid. As I had bought 85% formic acid and needed 60% it needed to be diluted, no big deal I thought until the bottle of formic acid slipped out of my wet gloves fell and bumped on the bottom of the bath where I was doing the dilution and sprayed 85% formic acid in my face. I got it on my cheeks and on my throat and a droplet in my eye. After dosing my face under the tap for about a minute, while all the formic acid went down the drain, I opened the bathroom door which my wife was about to break down having heard the commotion. After a visit to the doctor I had to have a large band aid covering my eye for a day and had to drop antibiotic liquid in my eye for three days. The burn marks in my face and throat were gone in a little over a week. It didn’t really hurt but the acid did burn in my eye. There is no lasting damage but I was obviously mortified that I could have been so clumsy and careless.

I finally bought a new bottle and performed the dilution at a lab of a biologist friend, no drama what soever…and the procedure with the hives went down without a hitch. I could have done it easily in a sink, the bath was not the best choice. You just have to be careful, wear eye and hand protection and be organized. And if all else fails find a place that sells it at the right concentration for your method or use a method that uses the 85% concentration.

So the take home message is; don’t spill formic acid in your eye, it hurts and is a major bother.