Hi Peter,
I would never even try to sample for varroa during the winter.  It is just too much messing with the cluster to get a proper sample from inside the cluster.  To take samples for other purposes i.e. tracheal mites and nosema and also wash the samples for varroa - why not wash them since you already have the samples.  If any varroa were found in such samples I would be doing some research and expect to do proper sampling of every colony in the yard as early in the spring as reasonable with the expectation that treatment would be needed at that time.

Now my experience.  I have not been using the strip treatments for close to 7 years ( can't remember exactly how long anymore ).  I have done drone brood removal, used formic acid gel, and all my colonies ( both of them right now ) are on mesh bottoms.  Currently trying SMR stock and am very impressed with it but that is a different discussion.  In that time I have lost many colonies to varroa ( remember that is not all that many colonies since I only have 2 - 4 colonies ).  They all died early in the winter - most didn't even make it to January.  Now these colonies had pretty substantial varroa populations but if the colonies survived to March they made it into the spring and I was usually able to keep them going until the next late fall/early winter.  Some needed treatment of some kind in the spring but drone brood removal usually did the trick at that point in terms of keeping them going until late November or December.  That is why the 4.5% winter loss indicated lack of problems to me.  I have had tracheal mite losses into this time of year but in that case more colonies were dead by mid January than died in March again limited experience but suggestive of a pattern.

How are things going at Cornell?

The beekeeping class at the U of MN was this past weekend and they had over 100 in the class.  A good bunch of folks eager to get into bees.  Spring can't be too far away!

blane


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Blane White
MN Dept of Agriculture
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