Jim said "In my view, spring treatments for varroa are useless. Think
about it - assume you have a single-digit mite fall using
whatever test method you wish. Since you have no chance
at all of killing all the mites in spring, you are exchanging one
small number of mites for another small number of mites, and
in the process, exposing bees, wax, and mites to a pesticide
during a period that may be too cool to allow the pesticide to
be fully effective."
Jim is certainly not alone in his opinion, but there is also much opinion,
and success, in using spring treatment.
Unless I am much mistaken, for many years Medhat Nasr, while at the
University of Guelph, advocated spring treatment with Apistan and fall
treatment with formic acid. Absent resistance, Apistan will kill 99.8% of
Varroa, leaving mite levels so low that they are unlikely to significantly
damage colonies in the summer. In the fall, formic will kill something like
85% of mites. I believe that formic might have been chosen for fall
treatment as the temperatures are likely to be higher in the fall than in
the spring, and formic will not work well in low temperatures.
The whole idea of not using two annual treatments of Apistan is to delay the
onset of resistance.
Lloyd
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Lloyd Spear Owner, Ross Rounds, Inc. The finest in comb honey production.
Visit our web site at http://www.rossrounds.com.
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