>>> > >Are there other references/experiences about treatment thresholds? > There is good graph in the following paper from Germany. Colony winter > mortality rises sharply at somewhere around 5 mites per 100 bees. One of my favourite sites for this topic is http://www.apinovar.com, although he uses drops instead of washes. Of particular interest: http://www.apinovar.com/articles/Varroa%20control%20with%20APINOVAR%20%28...%29.pdf http://www.apinovar.com/articles/flash.en.html http://www.apinovar.com/articles/Varroa_Winter_Losses.pdf I pulled this chart off one of his pages: http://www.honeybeeworld.com/diary/images/2012/ch20.h5.jpg *********************************************** 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