Disease Treatment - Formic Acid
Formic Acid (HCO2H), also known as hydrogen carboxylic acid, formylic acid, and aminic acid, is an organic acid that is commonly used in the manufacturing processes of textiles, leathers, cosmetics, and food production. It's name is derived from 'Formica' the latin name given to species of ant that spray the organic acid as a means of both attack and defence e.g. Formica aquilona - the Scottish Wood Ant, a keystone species of Scots Pine and Birch Woodlands. Formic acid is also found in the sting of the common nettle Urtica dioica and is naturally present in honey.
Note: Formic Acid is a colourless liquid with a pungent smell that vaporises at normal temperatures ( avg 20℃) and will irritate mucous membranes and burn skin tissue. Always read manufacturers safety guidelines before use. Also see the hazards page.
Uses in Beekeeping
Formic acid is the only soft chemical that is effective both against phoretic (on bees) and reproductive phases (in the capped brood) of the varroa mite (Rosenkranz et al., Citation 2010). It is found in varroa control products currently available in the Uk and approved by the Veterinary Medicines Directorate (VMD) e.g. MAQS, Varromed, Formicpro. It shows no signs of resistance build up, and is not known to cause residue build up in wax. Impregnated strips and trickle treatment are common methods of application.
Fumigating with Formic Acid is widely practised on the continent due to it's efficacy. Trials using a patented vapouriser with 60% Formic Acid have shown eradication of varroa mites at 89% during summer, and 96% during autumn, with a 90% eradication within sealed brood cells.
Evaporation - quick guide
Used as part of an IMP (Integrated Management Plan) varroa control is achieved by continuous evaporation treatments of formic acid over prescribed periods using an evaporator and a solution of formic acid. The following except gives an overview of the Nassenheider Evaporator Classic using 60% formic acid.
Recommended Treatments:
Note: Only suitable for use when temperatures are between 10℃ and 35℃ at the evaporator.
- #1 - July and August, 15/20ml per day 60% formic acid over 10 -14 days
- #2 - September, 10/15ml per day 60% formic acid over 10 - 14 days
- #3 - October, can only be applied using the Universal or Professional evaporators
Prerequisites:
- Presence of brood throughout treatment
- Frame arrangement in 'warm' orientation.
- Ensure the entrance is protected from wind.
Preparation:
- Honey harvest and inspection of the honey area prior to treatment.
- Closure of grid trays of all types.
- Normal opening of the entrance hole in accordance with the hive strength.
Sequence of the application:
July:- Introduction of feed directly with removal of the last honeycomb
- Counting of the natural mite fall
- For more than 5 mites/day: #1 treatment in July
- For less than 5 mites/day: #1 treatment in August:
- Use 60% formic acid (AS)
- Duration 10-14 days
- Continue feed
- Feeding as with number #1 treatment
- #2 treatment with 60% formic acid directly after feeding
- Duration 10-14 days
- #3 Treatment is only necessary if strong infestation is suspected or after re-invasion (e.g. due to robbing). Removal of remaining mite with 85% formic acid. Duration 10-14 days /- Brood can still be present.
- Because the brood activity decreases strongly in October, and that the Evaporator CLASSIC needs the brood nest temperature, this application is only possible with the advanced UNIVERSAL and PROFESSIONAL evoporators.
- IMPORTANT: Minimum treatment duration must be adhered to. Otherwise it is not effective over a complete brood cycle.
Nassenheider Evaporator Classic fitted using plastic cable ties due to the corrosive nature of formic acid. Stainless steel metalwork should be considered when using this product. The wick is critical for correct evaporation and should replaced for each use.
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