You can treat with honey supers on in North America and New Zealand. Formic acid is an organic acid that naturally occurs in honey. Formic Pro controls the vapour release of formic acid throughout the treatment period. By the end of treatment, formic acid levels in the hive reflect what naturally occurs in honey, when applied as per label.
All other countries do not have the approval to treat with honey supers on. Please consult the label for your country.