Quite interesting to look though bee-L what’s happening in US and Canada. When I was in Apimondia in Vancouver it was easy to see how little was done about alternative varroa control in North America, and still four years later the situation is the same compared to Europe. Yes, there is improvement, but not very fast.

From my experience I would stress Allens comment which is quite true

"we need a toolbox full of different miticides as well as genetic remedies to combat the Varroa,
and we need development and approval of same in an expeditious manner; our
industry depends upon it! “

Too many beekeepers and researchers get attached to one method or  miticide that they work with. Like us in Finland. 5 years ago many of us tought that formic was the final answer, but it was not. All alternative methods have larger variation in results than hard chemicals. When we raised the amount of formic to the levels that were enough in almost all hives, we started to see unwanted effects to bees.

So finally we come to the idea of  combining different applications. Like Peter has said, oxalic is not helping if you have too many mites in the fall when winter bees are developing.  That’s why we treat hives at this point with formic or thymol. But we use only small dosages of these and don’t get problems with dying brood from formic or large residues of thymol in hive products. For example hives with 1 langstroth box are treated with single treatment 10 g of thymol compared to Peters 4 times 8 g.

So we are only able to kill about 80 % of mites at this point, which is not enough in the long run, but is able to protect developing winter bees well.

By doing oxalic tricling late when there is no brood we minimize the amount if mites NEXT YEAR. This way there is no need for treatments before the end of  honey season in next year.

A  I have told you, we have been running this in about 230 hives for 4 years now, and I can say that it works. The hives are managed by about  16 beekeepers as a part of their normal operation.

Beekeepers who are willing to test for natural mite fall can often leave out formic/ thymol treatment when there is very few mites. Others must do two treatments to all of their hives.

The cost of these treatments, including the work needed is not more than treatment with Apistan. Also the commercial beekeepers have adopted these treatments. Although I must say that beekeeping is small here, commercial means here 300 – 600 hives.

I don’t believe that this double treatments will work in hives that have brood all the year around. But it will work in many parts of Europe and Northern America.

Ari Seppälä

Central Finland  62 N  24,5 E

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