I was re-reading a reprint of a November 1989 article in ABJ that I came across
while tidying (once every decade or so).  The title was : "The Control of
Parasitic Bee Mites: Varroa jacobsoni, Acarapis woodi and Tropilaelaps clarae
With Formic Acid'

The article shows the effect of 65% formic on the above three mites using a
simple, inexpensive application method.  One of the ways the cardboard pieces
were used was by placing on the hive floor.

I wonder what this does for the Small Hive Beetle?

allen
--
A Beekeeper's Diary: http://www.internode.net/HoneyBee/Diary/
Package installation & performance experiments, winter loss, fondant feeding,
Pierco vs. Permadent vs. dark comb, unwrapping bees, spring splitting tricks,
AFB, varroa, protein patties, daily mumblings and more... Thousands served...