Ted Albers writes:
Opened hive on 11/16/13 after a freeze. Could this be 'cold brood?' Note how many are head-down (to generate heat?) Not sure strength of hive before the freeze; plenty of honey but perhaps too far from center of hive. About 3 frames looked like this (clustered near one another.) Many fewer dead bees found than a full/robust hive should have so perhaps hive was already in decline. (Shelburne.) Thanks!
Mike Palmer Replies:
Yes, I would say the colony has been in decline for some time. While there are a number of bees head-first in open cells, indicating starvation, I don't believe the colony starved. I see colonies like this every year when I pick up winter losses. Diagnosis is confirmed by looking at the remaining cells of capped brood. In the lower left corner of your photograph, I see a worker that died while attempting to emerge from her cell. Do you see it? Open the cell with a pocket knife or the corner of your hive tool. Does she have fully formed wings? Does she have a normal sized abdomen, or is it flat and stunted?
I believe your colony perished from varroa/virus complex. The varroa population reached a critical level a month or more before you discovered the loss. As viruses spread through the colony, sick bees bailed from the hive in an attempt to get the disease away from the colony. Eventually, there weren't enough bees to maintain a viable cluster, and the perished.
I suggest you sample the mite load in your colonies at least twice during the season. The first sample should be taken at dandelion bloom, and a second by the end of July when you harvest the summer honey crop. This is the only way to know for sure what is happening with the mite population in your colony. Is it going up? Is it staying the same? If the mite count is already high in mid-May, more than 5%, you must treat at that point. The only treatment that is approved for use when the bees are making honey is formic acid, administered with Mite Away Quick Strips, or better known as MAQS. If the mite population is below 5%, you can wait to treat until after you remove the summer honey. At that point, sample again. If the mite load is again below the 5% treatment threshold, the colony can be supered for the Fall flow. If not, the colony must be treated for varroa. The goldenrod flow is usually finished by the end of August. At that time, any remaining supers should be removed, and the colony treated for varroa.
Remember that a honeybee colony requires a large population of young, healthy bees to winter successfully. The bees that raise the winter bees must also be healthy, so if your bees need a varroa treatment, get it on early.