2011 Ontario Treatment Recommendations for Honey Bee Disease and Mite Control Monitoring Method -- Number of Varroa Mites in August Ether Roll -- 2 mites/100 bees Alcohol Wash -- 3 mites/100 bees This translates to 6 or more per ether roll, 9 or more with the alcohol wash. These levels are not very high, and I would be surprised to see untreated colonies without these levels. Formic acid is less effective the later it is applied, but even a 60% knockdown could bring the levels down below these numbers. PLB *********************************************** 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