Hi Bob, Kirk & all.

A round is treating every hive in the operation, one time. Subsequent 
round is 3 to 7 days later.  This is a "flash" treatment, usually gone 
within 24 hrs.  Our experience is that exposure to formic under certain 
conditions for a longer period can be harmful to the colony.  Exterior 
temperatures and colony strength seem to be huge factors, which is why 
we feel products providing longer term exposure have success one, maybe 
multiple times and then can be complete disasters (heavy brood & queen 
losses).

We use Dri-loc 50s (hold 40ml of Formic) for our standard hives. Singles 
get 1 pad placed at the centre back (doubles - 2 pads side by side at 
back) on top of the brood frames (hive can be supered). For our 6 frame 
Nucs we use a Dri-loc 40s which hold 30 ml and treat them only in the 
fall.   We "charge" the pads at home beforehand. If applying while we do 
other hive work, we have small (3 kg honey) pails that hold 40 (usual 
yard size).  If basically just doing a round of Formic, we have large 
(15 kg honey) pails.  In these we carry 200.   Charged pads are frozen 
in an old chest  freezer and we take them to the field that way.  5 
small pails will fit in an insulated super, so these will tie nicely 
into the load if we're only working through 10-15 yards that day.  The 
big pails we just throw in old picnic coolers in the back of the pick 
up. The pads are applied just before we leave a yard by a couple of us 
in coveralls, using tongs, rubber gloves, respirators and safety 
glasses.  We always have eye wash and a bucket of fresh water with us in 
case of an accident.  We won't apply unless the temp is expected to rise 
above 10C in the next couple hours (won't start below 7-8C).  When the 
afternoon temp is going to exceed 25C we will stop applying them at 
about 20C.  This sometimes means that not all yards will receive both 
applications.

So why are we still doing this?  Good question and the totally 
unscientific answer is that the hives seem to do better afterward (even 
a couple days later).   We use Apivar for varroa and hopefully formic is 
preventing any possible resistance developing there. Tracheal mites are 
none existent, but there seems to something else going on.  We actually 
stopped doing the whole outfit for a couple years and during that time 
had a big hive crash the second winter. A couple things in our hive 
management had changed at that time, so can't say for sure it was the 
lack of formic.  What was interesting was that a few yards which had 
missed being treated with Apivar the previous spring, were showing 
higher mite counts going into the fall.  These were treated with Formic 
to get the Varroa populations down quickly and we also did a few more 
yards since we were out there.  The formic treated yards were the hives 
with the least issues.  This really stood out when we looked at yards 
(some treated, some not)  that were brought together to winter in one 
location. Since then, we've left some yards or half yards untreated and 
they seem to have slightly lower production and higher winter losses.  
Given our size, it's a relatively inexpensive & easy treatment (buy pads 
in bulk and formic by the barrel.  Dedicate a whole freezer), so we just 
do it.


Dave Tharle
T'N'T Apiaries
Ardmore, Alberta
Canada

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