Next on our race to finish reviewing last year’s MBA talks is Dr. Meghan Milbrath‘s Planning for Varroa. Oh, how we have dithered over this review. After all, the link we just gave takes you to an online version that is pretty much the same as what we heard minus a few pictures we are not going to try recreating. What could we add to simply pointing our visitors to it and encouraging them to read it? And yet most visitors seem not to follow links. Since Dr. Milbrath begins by pointing out that we are in the midst of a varroa epidemic it seems important that we at least try to provide a summary of sorts.

Here then is the rede as we understand it.

  • Monitor your mite load.
    • Alcohol wash or sugar roll.
    • At least monthly but especially when winter bees are being made.
  • Know the “safe” level of mites.
    • General consensus as of 2017 is 3% or 9 mites per standard 1/2 cup(100 ml) sample.
    • At levels above 5% illness is usually seen.
    • At levels above 10% the colony is a danger to those around it.
  • Know the tools for managing mite levels and be ready with a plan to treat.
    • Management methods to keep low mite levels low. Used all season to slow mite reproduction.
    • Intervention methods to drive high mite levels low. Used when mite levels are above threshold.
      • It is too late for non-chemical management techniques if the mite load is very high.
      • Vary chemical treatments to discourage development of immunity in the mites.
  • Make slow progress towards treatment-freedom.
    • Make splits of your colonies that require the least treatment.
    • Requeen your colonies that require excessive treatment with queens from resistant lineage, commercial or your own.

But I am hardcore treatment-free and my plan is to just let them die. Why should I monitor?

Please do not do that.

For one, these are useful creatures in our care to whom we owe better than an unpleasant, lingering death.

For another, they may have other useful genes which would be lost if varroa resistance were the only criterion considered.

Finally there may be colonies in the area successfully resisting low levels of varroa who, upon robbing your deadout, will acquire a number of hitch-hiking mites and may now succumb to the heavier mite load, losing good resistance genes for not being perfect. You will have made a varroa bomb.

But my bees seem fine. I do not see any mites. Why should I monitor?

Varroa is very hard to see on bees until it is too late. You will not know if you do not monitor.

But my bees have been surviving without interference for years. Why should I monitor?

Congratulations on your good fortune but conditions change. Dr. Milbrath had a bee-yard where a mere annual split was sufficient to keep mite loads low. The bees did the rest. Then one year the mite levels suddenly jumped. A neighbor had abandoned four hives which then died and became varroa bombs. Her own hives would have done likewise had she not caught the change and treated to push levels back to previous values. You will not know if you do not monitor.

But I got my bees from a treatment-free, resistant source. Why should I monitor?

Your conditions are not the conditions of your supplier. Mite pressure in their area may be lower than in yours. They may be able to manage them simply by all the making increase needed to have bees to sell. For whatever reasons, treatment-free success does not always transfer. You will not know if you do not monitor.

But this is a package’s first year. I need not worry until the second year, right?

One, wrong. We have made that mistake. Two, you know the refrain. You will not know if you do not monitor.

OK. My bees died over winter but it was the cold and damp, not mites.

Did you know what to look for when you inspected the deadout? We have used this excuse ourselves. We were wrong.

Fine. I will monitor. I’ll worry about a treatment when I need it. Which I won’t. Because I have good bees.

May your bees never need treatment but if they do, as with many an unexpected misfortune, it is better to have considered options and decided upon a plan well in advance rather than be forced into hasty decisions under pressure.


Gowry's painting of Icarus fallingOne imagines that after his initial, frantic flapping developed into deliberate, controlled flight Icarus was surely feeling rather confident at the moment just before the beeswax started to soften and the feathers to drop away. We too had our brief period of confidence when, after years of frozen deadouts, all three hives survived last winter, which we credit largely to finally managing varroa, especially applying an autumnal oxalic acid drizzle. With our freshly acquired knowledge and skill this season was going to be a change from our usual winter moaning over whether or not we would have any bees at all come springtime. Perhaps not.

We had tried to be timely this year with the oxalic treatment, beginning with Dorcas of the alarming mite counts, who took her medicine as calmly as last year. But when we continued to Clarissa she let us know that she was not receiving visitors, however well-intentioned, so we retreated to deal with stings, intending to try again another day. Whereupon the weather turned far too cold to be wetting bees and remained so as we applied the insulation to the hives, still hoping for a few warm days when we could treat the remaining two hives.

The hoped-for few warm days finally arrived last week and we returned with a fresh batch of oxalic syrup, this time planning to start with reliably even-tempered Beatrix and leave the stinging Clarissans last. But misfortune struck soon after we moved the follower board. The first top bar had two, large, partial combs that had not been merged into one and each was attached to a side of the hive. We had barely begun to cut away one attachment with the sharp end of the hive tool as we routinely do when a crack shot across the top of the comb and it suddenly dropped. Switching to a serrated knife we sometimes use, we tried to cut the other attachment but at once the second comb cracked free as well. At a loss for proceeding, we propped up the fallen combs to be next year’s problem, closed the hive, and abandoned our oxalic plans for the season.

So two hives did not get their oxalic treatment and the one that did had high mite counts before the expected autumnal rise. Once again we shall be fretting through winter. And muttering quiet blasphemies against Apollo.


Oh, had we but seen this video a few days earlier, in time for Halloween!

A three-minute thesis competition is a contest for PhD students in which they condense their thesis into a three minute presentation comprehensible to an intelligent audience lacking any background in the research area. Doctoral candidate Samuel Ramsey was the winner in such a competition at the University of Maryland and will go on to the worldwide competition. Congratulations, soon-to-be-Doctor Ramsey!

To present his findings even more briefly than the video, we have been assuming that varroa mites chiefly live on bee hemolyph but actually feed mainly upon the tissues in the bee’s abdomen known as fat body, a name that does not do justice to its nine important functions. Denied this food source and fed on only hemolyph the varroa do not live as long nor reproduce as well. So with a slightly strained metaphor we have been trying to stake vampires when we need a silver bullet for werewolves.

So it’s werewolves not vampires. And it’s Istanbul not Constantinople.

Seeming queenless is her one weakness.

Dorcas has been confusing us since June when we posted about finding her apparently queenless and broodless but calmly carrying on. Since then we have been able to check on her only infrequently either because we were giving a potential queen time to develop and start laying or because we simply lacked time during spells of suitable weather. When we did check we ever saw neither hoped-for sign of a laying queen nor dreaded evidence of laying worker.

We were able to more frequently observe her entrances and never saw anything amiss there. Traffic was lighter than at Clarissa or booming Beatrix but regular. No robbers. Just foragers going forth and returning, even some optimists heavily laden with pollen. And their numbers did not seem to increase but neither did they diminish. We did once see orientation flights but the timing was such that it could have been from the transplanted comb.

This last Sunday we finally had time and weather to inspect all three hives, beginning with devious Dorcas, the conundrum of the season, to find that she had a queen-in-hiding laying for all she was worth when we were no longer looking. Brood! Capped worker brood! Larvae! Dripping with nurse bees! And that is quite enough use of the exclamation point but we were inexpressibly relieved and elated. At least until we performed a sugar roll and measured thirty-four(34) mites in the sample! Oh, blast. Another exclamation point. You will forgive us when we point out that this measurement means over eleven(11) mites per hundred bees, which Bee Informed Partnership says is a level indicating “Loss of colony likely. Intervention is essential to decrease the threat of horizontal transmission (spread) of mites to neighboring colonies.” We immediately applied Mite Away Quick Strips(formic acid). She will surely need a second dose in a week and we must not be tardy. If weather will not permit time for another sugar roll then we shall simply raise the roof long enough to apply a second treatment and check mite levels again at a later date.

With such a high mite count in Dorcas we expected the worst for Clarissa and Beatrix but counted only a single mite in the former’s sample and none at all in the latter. Almost unbelievable good news. But bees may yet drift between hives so we shall have to remain vigilant against hitchhikers from Dorcas.

Where did the last two weeks go? On the eighth we visited the hives again to follow up on our first mite treatment.

Clarissa – We removed the old MiteAway Quick Strips and performed another sugar roll. The mite count was 7 (down from 16) for 21/3 mites per hundred bees. Not strictly high enough to treat but as we started with such a high count and are going into autumn we applied a second dose of strips.

Unrelated to mites, we spied a pair of bees energetically attacking a wax moth larva on the floor. We assisted by chopping it in twain with a hive tool after which the attackers lost interest. Apparently bees are sticklers for respecting job descriptions and killing intruders is very different from hauling out rubbish even when that includes dead intruders.

Dorcas – She continues to confuse us. No eggs or larvae. No queen spotted but no laying workers either. The brood frames we had transferred showed capped cells and we noticed a queen cell torn open at the side.

Beatrix – We left this hive alone.

Annabelle – Still sitting in the woodshop with only minimal progress towards redeploying her.

And that is the late report. We should have visited them again a week after that but life, weather, the usual. The same things that will probably keep us from inspecting them again as soon as we should.