Hi Everyone,

Allen writes:
>I can see you and I are looking at things from very different perspectives and this is quite fascinating.  I am a commercial beekeeper.  Losing one hive sixty miles away, especially if it is already over the hill, is of academic interest to me only....I am looking at the big picture and thinking of entire yards, rather than individual hives.

Peter Borst replied in part:

"OK. Say you are trying to determine levels of varroa in several apiaries as economically as possible. You took 175 bees per apiary, that is 175 per let's say 400,000 bees. Very low levels of infestation simply would not show up at this sampling rate. Plus, I think taking samples at the edge of the cluster is a mistake."

Peter, Allen also had another data point in the orginal post which would also give me a high level of comfort with his conclustions - 4.5% winter loss.  With that winter loss you know you are not pushing the economic threshold for varroa or tracheal mite problems.  I too are a little uncomfortable with the sampling method for varroa but winter survival data indicates no varroa problem.  Taking bees from the edge of the cluster is exactly what is suggested for nosema and tracheal mite sampling but not for varroa.  I would expect varroa to move to the center of the cluster over time and stay there so the bees at the outside of the cluster would have fewer varroa mites.  If the washing of the samples had found varroa, I would be concerned that there was a problem developing but the wintering results say otherwise.  

An interesting discussion.  Thanks Allen for giving us this live example to consider.

blane





pb


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Blane White
MN Dept of Agriculture
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