> I ...need to take some some action this spring against tracheal mites. ..
but am uncertain about where to get small quantities of
> good quality formic acid...How much would I need?

30 ml of 65% formic each for three treatments.  Total 90-100 ml per hive.

> Anyone have any suggestions on ready sources? I live in Maine.

Drug store.  High school chem teacher,  Chemical supply houses.  Indusrtrial
chemical supply.

> Also, I have considered as an alternative the menthol crystals and crisco
"blue shop towel" method of tracheal mite control in Allen Dick's site. Is
there any research on which is more effective?

Having used both, and having talked to other smart commercial beekeepers,
and having looked to see what the results were a year later, I can say there
is no comparison.  The shop towel method is by far the easiest, safest,
pleasant smelling, and most effective tracheal control method I've used.

I do not plan to use formic for tracheal alone again.  I *might* consider
formic for varroa and tracheal together if there is any sign of Apistan
resistance showing up.  Otherwise, it is menthol and grease all the way!

I used about 8 grams of menthol/hive once last year and can't find any mites
in a cursory exam this spring.  Previous to the Blue towel treatment, we
found lots every year without looking very hard.

...And don't let anyone tell you menthol needs hot weather.  If you use the
Blue shop towels, make sure it is not too warm out.  This method (the
menthol is mixed with Crisco and soaked into towels which are placed on the
top bars) works well if the days get up to 65 degrees F even if the nights
are freezing .  If your hives are wrapped the method may even work in
slightly cooler weather.

Just don't drive the bees out of the hive with it.

allen
http://www.internode.net/honeybee/diary/