Should I leave the screen bottom board open or close it off?

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Randy Oliver ( ran a trial with screen bottom boards and published the results in the February 2011 issue of American Bee Journal. There was a 4% to 5% reduction in efficacy compared to colonies treated in hives with solid bottom boards.

However, both open screen and solid bottom boards saw over 90% drop in mite loads. Mesh floor/screen bottom boards should be closed off to prevent formic vapours from dumping out. Bees are not built to move air up through a screen, so open mesh floors should not be considered as additional ventilation. The bottom hive entrance must be fully open during treatment.


Posted on

June 23, 2021