Hervé's post on the mathematical model and Varroa collapse triggered my thoughts on controlling the variables in any trial. The paper dealt only with Varroa so variables were controlled. 

Several of the collapses we have seen in Maine were a combination of Varroa and Tracheal.

It is a given that Tracheal has been around for a long time and most bees deal with it fairly well. Unfortunately, there were years before Varroa when widespread collapse occurred for no good reason but Tracheal was the apparent cause. 50 to 80% losses were not unusual. Tracheal modus is a gradual weakening of the colony and collapse during late winter. Varroa can cause collapse in any season.

Tracheal seems to operate on a cycle, that for quite some time everything seems under control then a year comes along when everyone loses bees. Then all goes quite again.

If Tracheal were added to the mathematical model, my guess is the Varroa mite load could be much less to cause collapse in a short time. That seems to be just what happened to one beekeeper who had high mite loads in the spring and lost most of his hives later in the year. CCD was blamed, but it is obvious that it was mites. Most of the CCD symptoms were there, so it is easy to pin the tail on that donkey.

Others in Maine lost bees, and mostly because of the dynamic duo, not Varroa alone. In most if not all cases, Tracheal was not treated for, since we all know that Tracheal resistant bees are the only ones we have. I treated the hive I lost for Varrao (OA) but not Tracheal for two years and the symptoms were classic Tracheal. It is interesting that some CCD symptoms are also Tracheal symptoms (as well as Varroa collapse symptoms).

This post is not to discount CCD, since it has been around several times before, or at least its identical twin (Disappearing Disease and Fall Dwindling disease). We live in interesting beekeeping times, and I would not discount a combination of mites to give rapid colony death which mimics CCD. Especially since that is exactly what happened to one CCD statistic.

We have a whole load of variables out there, all out of control and that include the beekeeper.

Bill Truesdell
Bath, Maine

******************************************************
* Full guidelines for BEE-L posting are at:          *
* http://www.honeybeeworld.com/bee-l/guidelines.htm  *
******************************************************