Upper entrances can be left open or closed during treatment.
Ventilation is critical when using both Formic Pro and Mite Away Quick Strips (MAQS). An entrance must be
provided that is the full width of the hive, typically the bottom board entrance, minimum height 1/2 inch or 1.3 mm. The bottom entrance must be fully open for the entire duration of treatment. Any restriction on the entrance into the brood chamber (e.g. reducer or mouse guard) must be removed to prevent excessive damage to the colonies. Screen bottom boards should be closed off during treatment to prevent formic acid vapor loss. Screen bottom boards should not be considered a source of fresh air as bees are not designed to move air up through the screen.