Let’s look at varroa: the study states that 3-lb packages were installed
on March 28. Surprisingly, “By May 21st, 2010 all twenty frames in each
of 20 hives were drawn out into comb and contained at least 14 frames of
capped brood.” These colonies really took off, meaning that they were
virtual varroa breeding grounds. By late July they averaged about 25,000
cells of sealed brood.
Strange and Calderone (2009) found Eastern package bees to contain about 3
mites per hundred bees, which would work out to about 300 mites in a 3-lb
package. When colonies are rapidly expanding, mite populations double each
month. So from late March through late July, we’d expect the mite
populations in these hives to reach 4,800 by late July. This is a very
serious mite infestation level! Yet, the researchers waited until October
5 to treat with Apistan strips (which are ineffective against mites in many
areas of the U.S.)! Any experienced beekeeper would suggest that these
colonies died from a varroa/Deformed Wing Virus epidemic, which leaves
deadouts, as the authors observed, “remarkably empty except for stores of
food and some pollen left on the frames.” Unfortunately, the authors only
included a photo of a honey frame, rather than a brood frame, which might
have been helpful in diagnosing the actual cause of death! The dosing with
high levels of an insecticide would be expected to cause the treated
colonies to suffer more from varroa than the untreated controls.
The description of the dead colonies does not match the definitive signs
of CCD at all—there was a dwindling of population, rather than a sudden
collapse, and no abandoned brood. Rather the descriptions of the deadouts
more closely matched dwindling collapse due to varroa/virus or nosema.
--
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com
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