FORMIC-ACID RESIDUES IN HONEY IN RELATION TO APPLICATION RATE AND TIMING OF FORMIC-ACID FOR CONTROL OF TRACHEAL MITES, ACARAPIS-WOODI (RENNIE)

Honey collected from formic acid treated and control colonies, infested by tracheal mites, Acarapis woodi (Rennie), as well as 17 Alberta and 8 southern British Columbia untreated honeys, were examined for formic acid content using a modification of an enzymatic analytical method. The formic acid residue level in honey collected in August from tracheal mite infested colonies treated with 88% formic acid in the spring, showed no difference from honey collected from the control colonies. However, the level of formic acid in honey collected from colonies treated with 65% formic acid in the summer, was significantly higher than honey collected from control colonies. Honey samples collected in various locations in Alberta had low levels of naturally occurring formic acid, whereas the honey samples collected from British Columbia had higher formic acid content. It is concluded that the formic acid residue levels in honey from treated colonies depend on the rate and timing of formic acid application for treatment of tracheal mites infestation. The level of naturally occurring formic acid in honey depends on the source of nectar.