Hello Bob, and all
Up here in upstate NY we were hearing reports of high levels by
August. I did ether rolls on 100 or so hives. Except for one yard of
24 packages, nearly every hive had high ether rolls for this time of
year. One yard, treated with Apistan in April, by mid August had 5
hives so far gone from varroa that I folded them. 5 more looked
hopeless, too sick to recover.  Only four from that yard looked
normal for this time of year. That yard was our very best yard in
spring, 14 strong triples.

The mite levels were overall about 10 per 250 bees, many in the 20 to
30 range and some well over 40. The package colonies were all strong,
made a super or two of honey in July, had levels of 0 to 2 mites over
250, which is par for mid August. In an area like this where there
migratory beekeepers, it is feasible that our hives have apistan or
even coumaphos resistant bees.

I have been told that in southern USA, people are maintaining bees
without treatments. David de Jong claims that untreated hives can
develop varroa tolerance (coexistence) and suggests foregoing
treatment as the route to get it. But in the Northeast USA, I believe
that this would not work. Untreated hives do not survive thru fall,
let alone winter.

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Peter Borst <[log in to unmask]>