At a field day of the Western Cape Bee Industry
Association, during which many of the substances
and methods of combating Varroa and/or it's
effects were discussed and evaluated, formic acid
was also considered. The day was held mainly to
evaluate the effects of Varroa and its resultant
treatment - if any - on beehives used for
intensive fruit pollination.

It was made clear that the APPLICATION of Formic
(protection of the bees from the acid and
determination of a dosage) is still one of the
problems that prevents regular use.

Two methods were discussed of applying the acid.
One made use of the typical inverted bottle system
inside the hive, for delivering a regular supply
of the vapour. The other method (my proposal) was
to saturate a piece of absorbent padding (check
the archives for more on this)  that was
previously slipped into a thin gauge plastic bag.

It had been noticed that bees will immediately
propolise up any absorbent padding containing
formic acid in the hives. It has also been noted
that bees will aggressively remove any thin gauge
plastic bags from their hives. The combination
means that the bees will start biting the bag to
remove it, releasing the vapour, and then have it
sealed up again. This process (and the even
osmotic movement of the gasses through the bag
material) should allow for a (fairly) regular
dosage of Formic vapour.

Trials have been done during the past spring
pollination season using the pad and bag method.
This method was decided on due to the lengthy time
the bees spend doing pollination without being
attended to. Any of the proprietary chemicals
would have needed removal over this time.
Beehives are moved in transit for up to four
hours, closed completely with a nylon mesh bag in
the entrance. Water is used to cool the hives in
transit.

Hives were provided with 30 ml of 80% (yes I know
about the queen loss potential) irrespective of
their size or condition. Pads were placed at the
back of the brood nest on the brood frames. Some
hives were not given anything. All hives that were
of pollination standard were rented out
successfully for an average of well over 2
pollinations per hive over nearly a three month
period

At the time of subjective evaluation after
pollination, it seems - throughout all 600
colonies - as if hives that had been provided with
Formic pads consistently showed better brood
pattern, more honey in the supers and overall
better health than did ones that were not. One
hive, accidentally given two pads (one on the
brood frames and one on the super frames) seemed
better than any of the others.

Drone brood was examined for Varroa and
consistently showed  no more than two Varroa per
cell. Most cells showed none, the average being
far below 0.5. (November is early summer and the
Northern hemisphere equivalent of May).

Not, granted, a scientific study, but one to add
my experience to the Formic debate.

Robert Post