>ISBA JOURNAL
>www.hoosierbuzz.com
>January - February 2001
>
>Also 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.
>
>Domestic stock results were, 9% for both, 21% with formic acid, 69%
>with screen, and 70% with no treatment. It was also found that the
>Russians are more hygienic then domestic stock.

As you can see, using screens alone was virtually identical to NO
screens. "69% with screen, and 70% with no treatment". Using a screen
with formic acid resulted in half as many mites. However, we found
that we could get the same results as this using a larger dose of
formic acid, with no screen.

I currently have an apiary of 24 hives started from packages in 2002.
Half are on screens, half are not.  The only reason I mention this is
to show that I am continuing to experiment with them, even though I
have never seen that they *do* anything at all.

That is, I will try different approaches regardless of my personal
bias. But this is the fourth year of testing them, and I have never
seen any effect: not on brood rearing, not on honey production, not
on mite levels.



--

Peter Borst <[log in to unmask]>