> : > > >Tested an IPM program of Screened bottoms, formic acid, both, and no > >treatment. Results were as follow for Russian stock - 1% to 8% using > >all four. Using both formic acid and screen did have lowest mite > >population, no treatment had highest mites but still low. Are we talking Tmites or Vmites?There is an article in the Oct.01 American Bee Journal detailing a study of tracheal mite levels in Russian stock versus a domestic strain,also with formic acid and screen bottoms.I havent had time to really wade through it,but it seems to say that Russian stock kept the Tmite levels below damaging levels without treatment,while the domestic strain did not.The researchers seemed surprised by the high levels in the domestic colonies as they were in Louisiana where Tmites are not generally considered a problem.They also noted that the screened bottoms enhanced the effect of the formic,rather than dissipating the fumes away,resulting in fewer mites than solid bottoms.I think they said that one treatment of the formic gell didnt reduce the mite levels in the domestic stock enough to prevent damage. The conclusion I am coming to is that formic in combination with stock that shows some resistance to both mites may be the best option for economical mite control ,because the writing is on the wall for the 'hard chemicals'.Some form of screen bottom seems necessary to monitor mite levels and for summer ventilation.I am not convinced that leaving the bottom open during the winter and spring is a good idea.The only study Ive seen shows reduced Fall and early spring brood rearing and says why this is a good thing.This is in direct opposition to the belief of many California beekeepers who go to great expense to get plenty of young bees in the hive ahead of almond pollination.So I guess its where you are and what you are trying to do that makes the difference. Mike (please excuse the date.this old machine refuses to send the right date despite expert advice on how to fix it) --------------------------------------------- This message was sent using InterStar WebMail