Here in California, we produce a lot of nucs each March and April for sale
and to restart our operation each season from nucs.

We start our nucs with cells, and dribble at Day 19 with oxalic acid, in
order to start the colonies with only a minimal mite infestation (typically
zero in an alcohol wash).  By July, most colonies approach or reach our
treatment threshold of 6 mites per 1/2-cup alcohol wash.  If left
untreated, the mite counts quickly climb, with counts of 30-40 by late
September not being uncommon (in test colonies that we don't treat.

If we didn't treat, we'd lose most colonies by the end of our relatively
mild winter.

That said, I'm currently grafting off of queen mothers whose colonies
somehow managed to keep mites at low levels all season long.

--
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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