Hi Guys, In Bob's recent posting it was proposed that thymol treatments were only effective if combined with an Apistan treatment during the same year. It's not that simple; in many European and other countries there is widespread resistance to pyrethroids, coumaphos and to amitraz. Many, many beekeepers are using thymol-based treatments WITHOUT the backup of an Apistan, Perizin or Apivar type treatments because they just don't work in some areas. So I can't agree with Bob's premise. In my own opinion, thymol/organic acid treatments of any type on their own may not provide the 97 - 98%+ control of mites every time such as we have seen with Apistan and some other treatments but sometimes they do. OK, the results between colonies may be more variable than with Apistan treatments but at least there is no resistance and mites are being eliminated from the hive. A further treatment of some sort may be necessary but isn't it worth it to overcome this plague of resistant mites? As far as I am aware, there is no wonder drug around the corner to replace Apistan [or Checkmite in The States]. Varroa resistance is serious trouble and will only be restrained (not eliminated) by IPM practices being introduced in treating our colonies. Monitoring is crucial to the success of IPM and good hive management. Chris Slade earlier referred to resistance reversion in varroa; from the European monitoring trials we have been involved in, pyrethroid resistance as a character may start to be reduced from a varroa population over the course of 4 years. It depends on many factors, not least the abstinence of any form of pyrethroid treatment within the region over a 3-4 year period, or longer. In the USA, where beekeepers are now seeing resistance to pyrethroids, to coumaphos and to amitraz, this is not going to disappear overnight; it will gradually grow and spread unless other methods are used. Thymol-based treatments such as Apiguard, organic acid treatments or biomechanical methods may not be everyone's preference but they may be more helpful than you think, whether the mites in your colonies are pesticide-resistant or not. I guess it's a matter of individual choice. Max Dr Max Watkins Vita (Europe) Limited 21/23 Wote Street Basingstoke Hampshire RG21 7NE UK Tel.: +44 (0) 1256 473177 Fax: +44 (0) 1256 473179 e-mail: [log in to unmask] web: http://www.vita-europe.com :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -- Visit www.honeybeeworld.com/BEE-L for rules, FAQ and other info --- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::