Greetings

I ran across this ad on the Internet

>Screened Bottom Board: $17.00
>Studies have shown that using a screened bottom board can
>dramatically reduce mite problems in your hive.

I have been unable to find any such studies, and researchers I have
talked with do not know of any. What I did find was this:

>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. -- ISBA JOURNAL.
>www.hoosierbuzz.com

Compare: 69% infestation rate with screens, 70% without. The screens
seem to double the effectiveness of formic acid, but you could get
the same rate by doubling the dose of formic.

Read also:
>IPM Management In Practice: A Case Study
>From MAAREC, the Mid-Atlantic Apiculture Research and Extension Consortium

Screens were not even mentioned as part of an IPM program.

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