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Date: | Mon, 14 May 2018 21:27:29 -0400 |
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Bill wrote: >>> Just a data point, but I treated both hives Friday and
mite counts Saturday
were 1 mite in the strong hive and zero in the weak hive. Recall from my
prior posts that both hives had mite counts after robbing/invasion in
Sept/Oct of about 4-600 for first treatment, 200 for second and about 100
for third and those were followed with a single Thanksgiving Friday
treatment. So more than five months have passed since the last treatment.<<<
Bill, I am following your notes on OAV with interest as you are relatively
close to my location and I am also evaluating OAV (fourth year using it
this year).
I am interested whether you were able to get a drop count for the last
treatment? My final treatments were Nov 19 - Dec 1, the Dec 1 treatment
was done at a temp of +5/+6C (about 41-43F). This final one gave a drop
of 3 mites/sq inch in scattered clusters. Most squares were nul, no
mites. I have not been counting total drop, but will try to do so this
year to enable experimentation with Randy's model. I would guess my last
treatment total drop was less than 50.
Do your colonies have open brood yet and are you concerned about using OAV
if so? I found mine very late to start brood rearing this spring due to
the cold weather, several had no brood at all on May 2 (hives are
insulated).
There was a discussion back in March regarding OAV and open brood but only
anecdotal information surfaced regarding adverse effects. I have searched
for published work regarding OAV/open brood effects, but pretty much all I
found was about OA dribble. The closest I got to something useful was:
Vaporisation of oxalic acid in a field trial with 1,509 colonies. Thomas
Radetzki (2001)
http://www.honeybeeworld.com/diary/files/__www.mellifera.de_engl2.pdf
However this was still not enlightening regarding actual effects of OAV on
brood. The author found a slightly lower efficacy of the OAV treatment if
brood were present, but did not report on any effects on the brood.
I am still evaluating spring mite levels and have not treated yet.
Rob Hughes
Upper Kingsclear, NB
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