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. -- [log in to unmask]