Date: Fri, 7 Feb 2003 19:18:54 +0200
From: komppa-seppala a t CO.INET.FI
Subject: Re: [BEE-L] how to fight varroa with organic acids

Allen dick wrote
> Aren't we all?  Chemical residues are definitely something to be worried
> about.   I understand that oxalic and formic do not leave noticeable
> residues, but I had heard that thymol can get into honey enough to be
> tasted?  Have you observed that?
> Have these treatments affected your honey yields or wintering at all, or
> have you studied that aspect of this approach?

> From my experience I would say that everything we use for varroa treatments
> ends up in small amounts sooner or later  to honey.  Formic acid treatments
> raise the amount of it in the honey. From Central European results we know
> that the natural amounts of  formic acid are very high in some honeydew
> honeys and the varroa treatments don't raise the  amount of formic acid even
> near these natural figures.    

Oxalic acid has not had so many residue studies, but we can say that the
residues are very small.

Thymol was a problem in the beginning in Switzerland and Germany when
beekeepers just poured chrystals into hives. About the same way as menthol is
used in the USA. If you have thymol treatment in the hive during the honeyflow
you can get residues that you can taste.  We only recommend to use it in the
fall once for about 3 weeks or whatever it takes to evaporate. We simply melt
the thymol in water bath and pour 12 g for 5 cm *15 cm wettex ( a commercial
kitchen cleaning cloth). One strip for hives with one box and two for a hive
with 2 boxes. Even this kind of short use leaves some residues ( from last
summer we could detect residues in about 50 % of samples) but these are about 1
% from the level detected by human senses. The residues don't increase from
year to year as they do with synthetic chemicals. Thymol is used in some sweets
and soft drinks.  Its also the main component of Apilife VAR varroa treatment.

As I told before all these three are also natural ingredients of  honey.

Overdoses kill bees, but when used according to recommendations we have had very
few problems. Thats why we have had the normal beekeepers to accept so widely
this way of varroa treatment.  


Ari Seppälä   MMM
Projektipäällikkö  Project Manager
Suomen Mehiläishoitajain Liitto r.y.
Finnish Beekeepers' Association
komppa-seppala a t