Practical Guide: 1.3.2 Dribble Treatment

Dribble treatment with oxalic acid is an established method in Switzerland for winter varroa control. Broodless colonies (or colonies with only open brood), correct preparation of the solution, and strict protective measures are essential, as oxalic acid is strongly irritating and harmful to health. The summary below is based exclusively on the official practical guide (BGD/SSA) and refers to the complete instructions/package leaflet.

Official Practical Guide (BGD / SSA) – Summary

Practical Guide: 1.3.2 Dribble Treatment (V 2507)

• Protective measures: Oxalic acid is strongly irritating and harmful to human health; always wear protective goggles, acid-resistant rubber gloves, and long-sleeved clothing.
• Required material: Oxuvar 5.7% (Andermatt BioVet AG) mixed with sugar or API-Bioxal dissolved in sugar syrup (API'GENEVE Sàrl); acid-resistant gloves and protective goggles; syringe with ml scale (possibly with rubber tube); grid-protected varroa bottom insert (for counting winter treatment mite fall); container with lukewarm water to warm and keep the dribble solution warm.
• Important points: Exclusively as a winter treatment; carry out only in broodless colonies or colonies with exclusively open brood (no earlier than November, no later than the end of December) – treatment is not effective in sealed cells; broodlessness can only be reliably determined by opening the colonies (if sealed brood is present: remove it or wait for a broodless period); prepared solution cannot be stored; for effective treatment, comb spaces must be free of wax bridges; outdoor temperature should (contrary to package leaflets) be below 5 °C; if more than 500 mites fall onto the insert within 2 weeks after oxalic acid winter treatment, a second oxalic acid treatment by evaporation or spraying must be carried out (Caution: perform only one dribble treatment!).
• Procedure (according to the practical guide): (1) Put on protective equipment (gloves, goggles). (2) Prepare the solution according to the package leaflet of Oxuvar 5.7% or API-Bioxal. (3) Place the container with the dribble solution in a vessel with warm water. (4) Dribble the solution with a syringe into the occupied comb spaces according to the package leaflet. (5) Close the bottom board (if open). (6) Insert the grid-protected varroa bottom insert.

► PDF of the official practical guide (DE)

► Official overview of practical guides (bienen.ch)
Note: Section Operational concept and practical guides → 1.3.2 “Dribble Treatment”.

Summary based on Practical Guide 1.3.2 (V 2507). Last review: 01/2026.

See also:

• Practical Guide 1.1: Varroa concept
• Practical Guide: 1.3.1 Spray treatment
• Practical Guide: 1.3.3 Oxalic acid sublimation
• Practical Guide: 1.5.1 Measurement of natural mite fall
• Recommended treatment regime against varroa