>>I checked my colonies regularly last winter, and  found that they 
were almost broodless (less than 12 capped cells) around New  Year. 

12 capped cells is not bad since, I believe, the OA concentration 
lasts for a couple of weeks.

I checked my colonies over the weekend.  They had 1-2 frames of 
mostly capped brood.  They were broodless at this time last year.

I guess I'll be applying the OA in mid-December. :)  I'll wait for a 
nice day with above-freezing temps to check for broodlessness.  I 
would not want to check the frames in sub-zero temps since some bees 
would try to fly and be lost.  But I agree that, once broodlessness 
is confirmed, OA can be dribbled in below 0 C weather.

Waldemar
Long Island, NY

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