Allan stated: In the case of drizzling 50 ml. of a 3.5% solution of the
dihydrate, very roughly speaking, less than 1.5 g of the actual acid is
applied directly to the bees, but is assumed to be ingested.


As far as I know: oxalic acid is a contact poison, which is NOT ingested by
the bees. However: mixing in a sugar solution is far more effective than
the pure 3.5% or 4% solution. I prefer trickling a ready-made oxalic
solution with contains also sugar, propolis as well, but could never
establish any ingesting by the bees: they ignore my wastage on the top
bars. Interesting to read is the following test: “Bee-to-bee contact drives
oxalic acid distribution in honey bee colonies”, Nicholas P. Aliano, Marion
D. Ellis, University Nebraska-Lincoln. Apidologie 39 (2008) 481–487
Do we know HOW oxalic application really works? My guess is still that it
works as a contact poison.



Very useful info is also in the following paper/proceedings of
"Coordination in Europe of research on integrated control of Varroa mites
in honey bee colonies". Proceedings from the Meeting November 13 and 14,
1999. Agricultural Research Centre-Ghent, Merelbeke, Belgium. I suppose:
paper can be found on the internet. If not found I will be happy to forward
it!



Geert van Eizenga? The Netherlands


-- 

Green Bee Consultancy
Drs.Geert Van Eizenga
Marnelaan 41
9727 DS Groningen/Holland
Tel.+31 505278909
Mob. +31616424299
Skype: g.c.van.eizenga

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html

Guidelines for posting to BEE-L can be found at:
http://honeybeeworld.com/bee-l/guidelines.htm