Hi Stephen,
 
In response to your note of 27 April, I do use wooden nest blocks for Osmia
but they can not be opened to clean out infested cells.  I have heard of the
treatments using Amitraz and Fluvalinate for honeybee mites and may try
these materials in the future.
 
At this time, the Osmia are in full nesting mode and seem to be using treated
and untreated blocks about equally.  While cleaning out some of last years
unopened cells I noted quite a bit of what I suspect is chalkbrood.  I have
heard of some experiments using Benlate to cure this in honeybee colonies
but have never tried it as my one chalkbrood hive produces at least as well
as my un-infected hives.  Any comments?
 
Finally, thanks to everyone for the interesting discussions on this line!  I'm
really enjoying "listening in".
 
Cheers!
 
Dave Pehling, WSU Cooperative Extension
Washington State
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