The use of formic acid in honey bees colonies ...
 
On Mon 24-MAY-1993 18:22:48.17 I sent a personal message to Kerry Clark,
answer to his personal question ... seems it could interest the
whole bee-l list though it's a bit too chem.
 
questions of Kerry :
 
<> Does formic acid also have such a fixed process of evaporation.
<> Specifically, are there "threshold" concentrations of liquid formic
<> acid that will produce different vapour concentrations?  This is of
<> interest because liquid formic acid may be used in beehives to kill
<> Varroa or tracheal mites. The usual 85 % concentration has been
<> associated with increased queen rejection, while 65 % is apparently
<> much less likely to result in such problem. Is there a way of
<> predicting what concentrations intermediate between these two, would
<> result in vapour concentration similar to that resulting from one or
<> the other?
<>
<> Do you have the equivalent values for the concentration of formic
<> acid/water that will evaporate from a 65 % formic acid liquid (and
<> does temperature affect the ratio as well as the rate of evaporation?)
<> from a 85 % formic liquid?
<>
<> I've heard the statement that formic acid "ionises" rather than
<> evaporates..  can you comment on the validity or implications of this
<> distinction?
 
my answer 24-MAY-1993 ...
 
> 1/ The problem of formic acid is whole different as that of acetic
> acid !  With formic acid, the azeotropic point give a boiling point of
> 107.1 DC superior to the boiling point of the pure elements (water
> [100DC] and formic acid [100.7DC]).  May be because formic acid could
> increase the hydrogen bonds of the water in the solution !  The
> concentration of the azeotropic mixture is 77% formic acid, 23% water.
>
> With this properties, the two different solutions you can use (65% and 85%)
> run quite different way when evaporating (remember azeotropic schemas) :
>
> - when you evaporate a 85% solution (over the azeotropic point), the vapour
> is more concentrate (I don't know the level but perhaps 90-95% formic acid)
> than the initial solution (85%).
>
> - when it is the 65% solution (before the azeotropic point), the vapour is
> less concentrate (perhaps 30-40% - I don't have the real values but it is
> possible).  You can imagine the difference of toxicity ! ?
> Evaporate vs ionise : I asked my colleagues about this question ...
> Sorry we don't know ...
>
> 2/ It is may be an anthropomorphic view but I don't like at all the use of
> formic acid to kill varroa or acarapis.  Actually we have some others drugs,
> not harmless but effective and smoother than formic acid which is, at the
> concentration used, a too dangerous product (see : causes severe burns, keep
> out of reach of children, don't inhale gas and vapour, in case of contact
> with eyes, rinse immediately with plenty of water and seek medical advice).
> It's very agressive material - try : inhale very carefully -> I don't wish
> that to my bees.  You never use a such treatment to another pet of you !?
> Furthermore, it attacks (as acetic acid, but harder) all the metallic
> hardware (iron !).  Seems to me it isn't to be used by common beekeeper.
>
> Hoping you have answer to your question.
> Regards                                               Jean-Marie
 
Actually the question comes again ...  My position has not changed at all.
 
Queens losses ?  Why ?  In my opinion it is not due to a direct action
of formic acid to the queen but to an important increase of the bees
agressivity (or protectionism?) against the queen - The case is well
known by the beekeepers, mostly outside the crops periods (winter and
first spring)(I don't know the english term but in french we say "la
reine est emballee" Jean-Pierre, peut-etre pourrais-tu traduire, merci!).
 
 
New forms of application ?  Ok !  Seems very important to avoid the
high concentration shock when the hive is treated => queen dead ...
Commercial gels and inserts seem beter than beekeepers ones.
 
 
Local blooming informations ...
Lat. : 4deg 56' E - Long. : 50deg 30' N  -  Alt. : 200 m  -  North sea : 200 km
 
My 12 production hives are gone yesterday (12-April) on the pear trees for
pollination (first blossoms fully blooming)(Conference variety)
very very cold weather (max 12 DC) but *they* announce more for saturday.
 
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 Jean-Marie Van Dyck                    Fax +32 81 72 42 72
 B.P. 102                               email : [log in to unmask]
 B-5000     NAMUR(Belgium)              Medical school - Biochemistry dept
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