I, as many on this list have been keeping bees since before varroa arrived on our shores so a bit of history by memory here. I trust Pete will correct what I get wrong, and I appreciate that.

My first encounter was I think 90 and had a few dead colonies in the the spring.  Varroa was newly the talk of beeks and the journals. Apistan (fluvalinate) was registered and I put some as directed into what appeared to my ignorant eyes as healthy colonies. Next morning the landing boards were covered with a layer of what looked like fine sand or some debris. Looking close I realized that I was seeing for the first time dead varroa. Thousands, probably many thousands, far too many to count and after less then 24 hours. The important point here is that the colony was at least surviving with that number of mites and that fluvalinate killed them very quickly.

Some time after at our state meeting we had Kieth Delaplane speak and he introduced, at least to me, the notion of "economic thresholds" contending that rather than treat by the calendar it would prolong the efficacy of control agents and promote the development of resistant bees to wait until a damaging threshold had been met and then treat. They were assuming that treatment would be >90% effective and could be delayed so as not to interfere with honey production. If memory serves I think they considered 70 mites a day on sticky boards natural drop to be the threshold in Georgia. Similar numbers came from Hood in South Carolina. Sheppard & Strange here in WA came out soon after with much lower numbers and using the either roll testing method. Marla Spivak was telling us to let the bees develop resistance and to practice IPM. I took it all to heart and in 05 lost 75%, by far my worst lose ever, before or since. The agents at the time were fluvalinate and coumophos both now ineffective and proven to contaminate comb and some early experiments with formic on mite wipes.

Sometime along there we came to the understanding that the real problem was the viruses that the mites were spreading, most notably DWV. The economic threshold started to fall like a stone. Colonies that once could tolerate a 25% infestation were dying with a 10%. Now in my experience it is closer to 3% in the fall in the north. Our hopes that the efficacy would be prolonged and that the bees tolerance would improve have not to this point been realized. We have discussed here at length the reasons.

I believe that the idea of waiting for a given infestation to be reached needs a new look. I hear the howls of protest and fully understand arguments for the practice. Because beekeeping did not provide the wealth beyond avarice that I had hoped I had to spend my career swinging a hammer outside in the winter. What I learned was that the way to stay warm was not to get cold. Sounds simple but it is true that it is much easier, and more comfortable,to layer-up and keep warm than to try to get warm again once you have become chilled. How does this relate to mite management? If you are keeping bees for profit, in my case honey, you have limited time windows when you can treat. Experience has taught me, and Randy has expertly demonstrated, that annual mite loads follow a fairly predictable curve and that early intervention has great benefit in keeping the numbers low. Even old Ben must have been thinking of bees when he said "a stitch in time saves nine". 

Now a colony that reaches >6% or so at any point in the season is probably doomed even if you are successful at getting the number back down due to the lingering effect of the viruses. That is my opinion only not backed by controlled study. I treat in early spring as a matter of course on the theory that even if I don't detect >1% I know that by August it will be >3%, in the danger zone. I treat early winter as a matter of course because it is not suitable weather for doing counts and an OA dribble I believe is fairly harmless and cheap insurance. I do what I have to to get to <1% in late summer. That leaves only the few occasions where a colony is in clear trouble during the season and supers must come off for an emergency treatment and loss of valuable crop. My annual loss rates are negligibly with this regime. 

OK, I'm perpetuating the problem. Keeping susceptible bees, although I do breed from WSU stock and we are making some progress. I am leading to resistance to registered products, although I rotate among formic, oxalic, hop acids, and amatraz. If it works and is legal my theory is get it while you can. What is the benefit of waiting until it does not work? I know that the mites will be with us for the foreseeable future and sincerely long for resistant stock but this year and probably next I will aim for the lowest mite counts I can manage. Researchers, full speed ahead and good luck. Common beeks like me keep the little buggers at bay the best you can.

Paul Hosticka
Dayton WA

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