Dear Ivan,

In our experiments with formic acid, we found that 85% formic acid
may interfere with the pheromones in the bee hives and will cause
increased agressive behaviour of workers against their queens. This
will lead to killing up to 50% of their queens. We also found that
85%  of formic acid can kill eggs and young larvae. As a result, it
will be difficult for the colony to raise queens to replace the
killed ones.

Using the 65% formic acid is less harmful to queens and workers. It
will not effect queens and drones longevity and performance as long
as the acid applied at the right time of the year and within the
recommended temperature range. In our studies, we also found that
the formic acid will kill workers and queens infested with tracheal
mites more radially than healthy ones.

We have been using formic acid (65%) single application pad in spring
for tracheal mite and varroa mite control in Ontario for the last 6
years with no reported queen failures or weak colonies.

Best Regards.

Medhat Nasr

Medhat Nasr, Ph.D.
Research Scientist,
Ontario Beekeepers' Association
Dept. Environmental Biology
University of Guelph
Guelph, Ontario, Canada
N1G 2W1
Tel: (519) 824-4120
Fax:(519)837-0442
e-mail: [log in to unmask]