> :
>
> >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)

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