Thanks for the references, Bil persistence of synthetic acaricides ... has led to the increased use of alternative control measures with non-toxic substances such as thymol and organic acids. Oxalic and formic acids are natural honey constituents, widely used in the frame of alternative V. destructor control. They have a GRAS status (Generally Recognised As Safe) and the establishment of a MRL is not necessary Long-term use of formic acid, applied according to the prescriptions, does not lead to an acid increase, but if used during the honey flow, residues might be high enough to change the honey taste (Bogdanov et al., 2002a). Single or repeated treatments with oxalic acid do not lead to accumulation of residues in honey The results summarised in this section show that Varroa control with natural acaricides like organic acids and thymol is a good alternative to treatments with synthetic substances. Contaminants of bee products Stefan BOGDANOV Apidologie 37 (2006) 1–18 *********************************************** 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