Expect Another 35% Loss in U.S. Bees to Colony Collapse Disorder This Winter

Beekeepers have to scratch this season to find much to be thankful for.

Too-cool, too-rainy weather almost everywhere gave American farmers great soybean and field corn crops this season, but kept summer blossoms from producing much nectar and kept bees from gathering what little there was. In lots of places (the Dakotas and Midwest and much of the east) the bees were barely able to keep up with feeding themselves and their young this summer. Everything they gathered they turned into more bees ... and, unfortunately, more mites. Excess honey just wasn't in the equation, leading to the worst honey crop ever, as reported here.

Down south and out west the dry, hot conditions accomplished basically the same thing. There was just enough, and too often not quite enough food to keep the bees going. They barely made it though the early and mid part of the season. Lots of bees, but no honey. Then, in the Midwest, especially the bountiful Dakotas and the surrounding states, the weather took on a kinder, gentler attitude in late summer, and beekeepers and their bees actually began gathering more honey than they could use. Surplus is what we call that honey ... and it puts food on the table and pays the bills. But there's a hitch.

Good varroa mite management dictates that beekeepers strive to reduce the number of varroa in a colony as early in the spring as possible so there's hardly any stress from varroa during the summer while the bees are raising brood and making honey. More importantly, all treatments have to be removed before the bees start making honey so that honey and varroa treatment chemicals don't mix.

But sometimes treatments don't work. Some are temperature-sensitive, so if it's too warm or too cold they aren't effective. Sometimes beekeepers can't get to the bees because spring is late and there's still snow and mud all over. And even when treatment are both well-timed and effective you never get them all so any remaining mites continue to breed unhindered all summer long, building to what can be a huge population later in the summer, unchecked and unchallenged. So in late summer, as soon as the bees quit making honey, beekeepers rush to get treatments back on to tackle what now is usually a large population of mites, again.

When days shorten several behavior changes occur in beehives, the most obvious being that the egg-laying rate of the queen slows. In fact, sometimes it stops. The adult honey bee population of the hive for most of the winter into early spring is determined then. But if treatments are held up for any reason all those female varroa, now at peak population because they have been reproducing like mad all summer on the brood produced all summer and they continue to breed on the bees that are there. What happens is that 2, 3, sometimes more females invade every available brood cell, instead of the usual single female ... and that's a slow-death sentence for each of the baby bees so brutally violated. Beekeepers try to get a fall varroa treatment on before this gets out of hand because they want healthy bees in their hives all winter and into the spring until they can get back to them for additional treatment if necessary.

Meanwhile, until treatments are administered, because there just aren't enough baby bees to feast on hungry mites attack adult bees in the hive. So, without treatments even hives with a moderate infestation of varroa mites can be tremendously compromised. Injured adult bees don't live as long, can't keep the hive warm when it gets cold and can't take care of any young the queen begins to produce. This hive is doomed.

Without controlling varroa mites after the honey season the bees in infested hives have a death sentence handed to them – to be carried out in a long, slow process that is complete around Christmas. But timing can be variable ... sooner, if it's warm, like Southern California; longer if cold, like central Minnesota. But the sentence is certain.

Beekeepers that treated on time will be OK this winter and for almond pollination in February, but colonies that got treated late are going to be small, and probably not large enough for the orchards.

I admit, this biology lesson is a bit over-simplified but it hits the main points. Not included are the combined effects of viruses and varroa, the fact that the way bees store food in the hive in winter is different than the summer and can restrict brood rearing space, and the insidious presence of pesticides collected, stored and consumed. The deck is stacked, no question.

The Devil's Bargain: Honey or Almonds

So, beekeepers this year had a tough choice. When the weather broke and their bees finally started making honey they could stop on time and treat as usual, and not make any honey, or money this year. Or, they could gamble and hope and pray that the varroa infestations they have are light enough that they aren't signing the death sentence that's certain by waiting too long.

This is a pattern that's been seen before. Colonies that die in the winter because of undertreated, or untreated varroa mite infestations in the fall are common, even in the age of Colony Collapse Disorder.

This coming winter is going to be deadly. Beekeepers who didn't treat, or treated too late because then needed the honey will lose colonies, and colonies that live will be small and challenged to grow. And, for many, maybe most of these beekeepers, small, weak colonies are just what they don't need for that February pollination contract in California.

So what does that mean for winter losses this year? I've talked to several beekeepers who are predicting another 35% or more loss this winter.

This isn't new. But maybe you should be just a little bit scared. Colony Collapse Disorder has been around for only 3 or 4 years. Varroa's been here for a quarter century and we haven't figured out either one of them yet.

Why, do you suppose?