Subject: Formic acid, varroa, etc.
From: "George W.D. Fielder" <[email-masked]>

[email-masked]
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Eric Abell wrote:
>It has been my understanding that the acid
>will not kill the mites beneath the capping.  If you have a way to treat
the
>brood with Formic acid would you please elaborate.

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While awaiting news of  the method the author had in mind, I thought that I
would add that last November there was a presentation at the OBA (Ontario
Beekeepers Association) convention about mite control with Formic acid,
 From what I remember it did indeed kill the mites under the cappings since
the fumes travelled through the wax cappings much as water vapour does.

In a nutshell:
Place a 8" X 9.5" piece of .5" thick tentest (Homosote) in a 12" X 12.4"
Ziploc vegetable bag and soak in 250ml of 65% Formic acid until all was
absorbed,  Place on top of brood frames on .5" thick spacers.  Place a 1"
rim around the brood chamber to accommodate this and cover hive.  Leave for
15 to 21 days.  During treatment the temperature should be between 12 and 25
degrees Centigrade with night temperatures not below 7 degrees C.  All
materials and technique are critical in order to obtain the wanted
evaporation rate of 10 ml./day which kills the mites and has no significant
effect on brood.  Treatment must stop before honey supers are put on.

BTW Formic acid treatment is legal in Canada, This vapour treatment is
recommended to use in spring along with Apistan (a contact chemical spread
by the bees as they crawl over the strips).  These two different chemicals
and method of transport help to avoid breeding resistant mites.

BTW2 I understand that Formic acid is effective for controlling BOTH Varroa
and Tracheal mites.

BTW3 Drone trapping is being used by some here when mite build-up is
observed but during honey flow in on and thus no chemical treatment can be
used.

george fielder