The new pandemic has us emulating our bees in this time of year, huddling at home except to occasionally forage in a lacuna-ridden foodscape and largely living on what we had stored. We generally try to keep pantry and freezer rather full and, thanks to the perspicacity of the Mrs, had gently augmented our stores over a few weeks before the panic-buying locusts struck. Thus far we are healthy and fed and hope to continue in that state. We wish the same for our readership. Meanwhile, let us write about the old, familiar pandemic which plagues our bees, varroa.

We have found the autumnal oxalic treatment against varroa to be critical in our hives surviving the winter. Unfortunately an oxalic drip/drench is annoying because bars need to be separated and we must juggle syringe and container of treatment solution.

Vaporizers may be faster and can be used when one does not wish to risk wetting bees but the commercial ones do not fit our entrance holes. We considered trying to homebrew something but out typical overdesign process quickly ran aground.

A more determined local beekeeper in charge of a few Kenyan-style top bar hives modified their end entrances to accept a commercial vaporizer wand. Alas, the treatment proved ineffective because the vapor did not drift the length of the hive. In a vertical hive it would rise up at least enough to cover the brood nest.

That leaves a third, recent alternative of foggers, which have thin nozzles. Rather than trying to sublimate solid oxalic acid they use a fine vapor of oxalic acid solution. In a horizontal hive one would expect the same problem of insufficient vapor drift from an entrance, but if spraying into each of many entrances along the side, there is hope. While some beekeepers repurpose the insect foggers available from yard and garden centers, last October we opted to try one made specifically for beekeeping, the Varomorus fogger.

Unsurprisingly a propane tank is not included. And while a breathing mask is part of the kit, we opted to get more substantial masks.

We have seen videos of people using the apparatus without protective gear but that strikes us as foolhardy.

It does look somewhat awkward but is easy to use. The pistol trigger is just the igniter for the propane while the control to feed liquid is another lever under the solution tank. We found it simple to use one hand to hold it by the propane tank and the other to pump the lever.

The company has already re-engineered the solution tank attachment for easier assembly than earlier models allowed so there is hope that the form factor of later models may improve. Their customer service is very responsive.

We were concerned about spreading hot vapor into the hive but, as the thermal image of us firing the fogger outside shows, the fine vapor quickly cools to ambient temperature. Even the hand, seen at left of image, holding the apparatus is warmer.

The instructions that come with the device specify using ethanol as the solvent for the oxalic. We were timorously intending to use water instead but, after seeing so many others around the web specify ethanol, compromised on hundred-proof vodka. Presumably the ethanol is faster than water in evaporating and cooling the spray but we could not convince ourselves that spraying a flammable, vaporized liquid into a wooden structure would end well.

We had already corked all but one entrance of each hive as the weather turned colder. Now after one of us sprayed a few bursts at various angles into the remaining entrance hole, the other corked the entrance. Then uncork the next hole and repeat down the length of the occupied part of the hive. After all holes were corked, we waited a minute or so and then uncorked the single winter entrance. Then we subjected the next hive to the procedure.

This all took very little time at all. An electric vaporizer would require a cooldown and warmup period between applications. And the propane tank fuels many more applications than the usual car battery, unless one can bring the entire car to the hives. The varomorus is much more portable.

Then we stood there watching the hives. As with previous oxalic treatments the bees did not seem at all inclined to attack but there was a slow stream of bees leaving the hives and dropping to the ground, where they would crawl about. While we wondered aghast whether it was heat, acid, or alcohol that had injured them, the stream slowed and stopped after a score or so of bees. We scooped up half a dozen into a small jar with screened top and took them indoors. The next morning one of the six seemed perfectly fine. One weakly moving. The rest seemed dead. Perhaps we had been overenthusiastic in our spraying. Peeking through the observation windows showed bees at work as usual. Not the carnage we had feared.

Now in late March we have seen clouds of bees flying from both hives on the warm days. So far, so good but proper springtime, not that equinox pretender, is yet to come.

Long time readers will recognize the significance of the black border. Yes, we are once again bee-less. We long suspected that Beatrix and Frankie had died when we saw no flights on the few, isolated, warm days but Dorcas still reliably produced clouds until recently and we had been counting on splitting her to repopulate our beeyard.

We began this warm weekend by opening Dorcas and found moldy but largely empty honeycomb without any sign of varroa crystals in the cells. As we cut away and discarded the combs an increasing number of neighborhood bees began arriving to mock us and clean up the dribs and drabs of honey we were spilling. We should have looked for mites among the dead bees carpeting the floor but forgot. We are poor coroners in the throes of grief. Our suspicion is that she died of starvation. We did pop in a feeder a few weeks ago but it was too late.

Moving on to Beatrix we found, except for the carpet of dead bees, a textbook case of winter death by varroa. A formerly populous colony reduced to a tiny cluster among much honey and the telltale varroa crystals in empty cells. Not entirely unexpected. We have learned the importance of a late season oxalic treatment but life kept us from applying it last year. The honeycombs were quite moldy. We would be denied the honey harvest consolation of our previous deadouts.

Finally in Frankie we managed to find a little honeycomb that was not moldy along with another dead bee carpet. No varroa crystals. Our guess is that she simply had not grown large enough to keep herself warm in spite of all the insulation we added.

We found a few, dead small hive beetles in Beatrix and Frankie. The bees apparently kept them under control until they could die together. No sign of wax moth either. None of the combs were slimed by either pest.

The bags of silica gel were saturated and we had the passing thought that they had, perhaps, been less effective than the wool we had used and the bees got damp. But then we considered that the bees themselves manage to keep air circulating to control humidity and, just as the mold appears after there are too few bees for this task, so too might the bags have become sodden after most bees were dead. A result, not a cause.

In our misplaced confidence we did not order any just-in-case nucs or packages so it is not clear where we shall get our bees for the season. Perhaps another swarm will visit our apple tree but we can not count on that. At least we will be able to perform various intended repairs and modifications on empty hives without troubling any stinging residents. Not exactly a silver lining.


Blackclad hives in the snowThree months without blogging! And still with a backlog of drafts from the Michigan Beekeepers Association Spring Conference last March. We have been neglecting our readership almost as much as we have been neglecting our bees. By now we have had our first two snowfalls and while poor, empty Clarissa is by the barn, flipped roofless onto her stand lest mice occupy her before we can once again fill her with bees, the occupied hives are in a row, dressed in their winter black. We also have several one-pound bags of silica gel in their unoccupied halves to absorb moisture. They should work as well as the wool we had been using and be reusable next season after a spell in the oven. Sadly this is nearly all the winter care we have provided this season.

Master beekeeper Rusty Burlew has great overwintering success and attributes it to always doing what the bees need without delay or excuse. By contrast, we, slackers, in many of our blog posts lament trying to find a suitable window to tend to our few hives, when weather, our paying jobs, and other commitments combine to allow sufficient bee time. This year we did not even apply the late season oxalic drip although we are convinced it has been the largest factor in what overwintering success we have had. Although the mite loads have been low, almost nonexistent, all season they could still climb rapidly in late fall. Rather than sugar roll to check we hastily applied some formic acid pads while weather was still in the effective temperature range.

And for even more fretting, a late peek into the hives revealed that Beatrix and Frankie had, in what seemed to us a very sudden outbreak, small hive beetles. Fortunately the bees seemed to be keeping them adequately confined. Without time to make the boric acid bait for the traps we used six years ago, we hastily added along side the silica gel bags some strips of Swiffer pad to tangle-trap the tiny beetles.

Our winter fretting this season will be laden with guilt.

Somehow we have not yet published a single post from this year’s Michigan Beekeepers Association Spring Conference back in March. And there are only eight months left until the next one, which our past reporting performance indicates is not much time at all. Let us then hastily commence.

Dr. Milbrath of the Sandhill reprised her Plan for Varroa talk from last year to a large and interested audience. Having already written about last year’s version of this talk we need not repeat ourselves but we shall post a few useful links.

We have dawdled enough that a revised version of the talk is available for viewing along with other recordings of webinars from Michigan State University’s Pollinator Initiative.

And there is an education section on her apiary website with links to articles on many aspects of beekeeping. The most relevant to varroa are:

We hardly need write anything further but we shall anyway.

Having heard the talk before we were better able to note smaller points that were overshadowed by the main message in the first hearing.

Some of the beekeepers who avoid treating their bees do so out of an attempt to stay “organic” and avoid “chemicals”. However organic farming standards do not allow the farmer to withhold treatment from a sick animal even if that treatment is not organic. Do honey bees under our care deserve less than cows or sheep?

Suddenly high mite levels can occur to anyone at any time. If you have been monitoring and treating responsibly then it is not your fault. You can not control hitch-hiking varroa from other colonies.

Although unnecessary treatments are to be avoided, allowances can be made for overwhelmed first-year beekeepers, who have so much to learn. Such a beek may simply treat by the calendar to keep varroa levels low while acquiring the skills to monitor in the next year.

Mite levels do tend to spike in the fall. Bees are reducing their population while the mites continue to increase theirs so the measure of mites per bee rises quickly. If you have observed this in previous seasons then using your local knowledge to treat in anticipation is permissible.

In a similar vein if you have lost colonies to varroa in previous years then treating by calendar to keep levels down is not “treatment”. It is “control”.

Let us end with a few words about our own monitoring. Wee Angharad has not yet suffered the indignity of a sugar roll. Dorcas a month ago scored zero mites in the sample. We shall be retesting her soon. Beatrix and Clarissa were tested just last week and also scored zero mites. We can hardly believe the low scores but it is yet early and they have each had a brood break for one reason or another. We shall remain vigilant.

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.