> I want to know what number would make you reach for a treatment.

Since I'm not seeing any answers to your question, Dick, I'll give it a
shot.
First point, sugar rolls only dislodge about 70% of mites, so they
underestimate actual infestation.
Second, let's use 300 bees--easier math, plus that is 3/4" of bees in a
quart mason jar.

Spring--I'd be concerned if over 1-2%; that would be 2-5 mites (I'm much
happier with only 1-2)
Summer--wouldn't put on supers if over 2%--5 mites
Aug 15 (can't wait until Sept)--maybe 5% max; 10 mites, but I would be
concerned at that level.
Fall--get back down to 1-5%; 2-10 mites.

All the above figures are not engraved in stone, but are dependent upon
stock of bees (some can handle more mites, such as Russians); the level of
viruses in your operation (this is the most important factor); the nutrition
of the colonies (better fed can handle more mites); the presence of nosema
(mites + nosema +viruses = death); the weather (cold and wet favor mites and
viruses). the presence of tracheal mite (two mites together can be fatal).
Also, take in to account how much mite load your colonies tend to pick up
from drift from outside sources.  The larger your operation, the lower the
"safe" level of mites.

I wish that there were a simple answer.  The simplest would be to stay below
2 mites per 100 bees all the time.

Randy Oliver

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