The study outlined in several posts in the last week that suggests that
screened bottom boards aren't effective against varroa seems to miss one
point.

Everything I have read says that formic acid and apistan treatments don't
kill varroa, but give them enough of a jolt to knock them out and make them
drop them off the bee onto the bottom of the hive. If that is true then the
mites wake up later with a bit of a headache and simply catch the next bee
north. Unless, of course, they have dropped all the way to the ground
through a screened bottom board.

Indeed, accordinging to the post of the fellow (Peter) who participated in
the study, when the hives combined treatment with screened bottom boards:

"The two treated yards had very low mite count."

The studies that have been quoted don't correlate use of screened bottom
boards with use of formic acid or apistan treatments.

Maybe I missed something in one of the posts that disputes
this...Nevertheless, this is an interesting area of study and I would be
interested in hearing other ideas along the same lines.

For the record, I put all of my hives on screened bottom boards in the early
part of the season, treated with formic acid in the spring and apistan in
the fall and all of my hives went into the winter very strong. This despite
losing 80% of my apiary to mites two years ago.

               Jay Mowat
             WILLOW CREEK
phone: 519-833-7238 fax: 519-833-0347
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