> > >Good thing I caught that one at 14%. If it were only that simple! It's not the mite, at any level of infestation, that kills the colony--it's the parasite/nutrition/lack of recruitment that takes the colony down. The mite acts a vector of viruses, and general stressor. If the colony has adequate nutrition and high recruitment from expanding its broodrearing, it may be able to handle a high mite infestation. On the other hand, if there is a virulent virus, combination of viruses, or viruses and nosema present, the colony may succumb at even a low or nonexistent mite infestation. Or, as Canadian bee breeder Liz Huxter noted, some of the best survivor colonies had fairly high mite levels going into winter, but apparently were more resistant to the viruses. And as Dr. Frank Eischen has observed, once parasites have stressed a colony severely, the additional stress of treatment may be too much for it to handle. There is no way to come up with absolute tip-point treatment thresholds, no matter the method of monitoring for mites. However, *in general*, the mite wash percentages that Bob and I mentioned are fairly reliable predictors. -- Randy Oliver Grass Valley, CA www.ScientificBeekeeping.com *********************************************** 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