Practical Guide: 1.2.1 Liebig dispenser

Summer treatment is a central component of varroa control in Switzerland. The Liebig dispenser is a widely used method for the application of formic acid (Formivar) and requires correct handling to ensure both efficacy and tolerability. The summary below is based exclusively on the official practical guide (BGD/SSA) and refers to the complete instructions.

Official Practical Guide (BGD / SSA) – Summary

Practical Guide: 1.2.1. Liebig Dispenser (V 2505)

• Protective measures: Formic acid (Formivar) is highly corrosive; always wear protective goggles, acid-resistant rubber gloves, and long-sleeved clothing.
• Required material: Liebig dispenser (attention: use the new low bottle only with the new base plate), wick paper (for double-sided printed wick, use only the paper with the version designation at the bottom right), adjust wick size according to the latest recommendation of Andermatt BioVet AG, Formivar 85% or 60% (Andermatt BioVet AG), acid-resistant gloves and protective goggles (protective mask), container with water (for rapid rinsing of any acid splashes).
• Important points: First treatment before the end of July (after the honey harvest), second treatment (two-week interval) to begin no later than mid-September; at temperatures above 25 °C generally use only Formivar 60% to minimise the risk of queen losses or brood damage; evaporation space: 1 empty honey super promotes proper evaporation (in the Swiss hive additionally seal upwards with a foam cushion if necessary); preferably place the dispenser early in the morning (when it is still cool); colonies must have access to open feed during treatment; disturb colonies as little as possible when placing the dispenser; do not feed during treatment; Caution: Formic acid must be at ambient temperature and must never enter the colonies cold (otherwise expansion may force excessive acid out of the bottle).
• Procedure (according to the practical guide): Strictly follow the dispenser instructions for use. (1) Put on protective equipment. (2) Fill the bottle in a safe place with the correct amount of acid (see instructions for use). (3) With open mesh floors, close the bottom board (ideally 1 week before treatment; improves efficacy). (4) Leave the entrance open (fully open in Swiss hive). (5) Attach the wick surface according to the instructions; place the base plate with wick paper in the centre of the brood frame lugs so that the paper covers as many brood combs as possible. (6) Place the formic acid bottle with drip insert onto the base plate. (7) Provide evaporation space (in a magazine hive: empty feeder or honey super). (8) Monitor the evaporation rate after 24 hours; adjust the wick surface if necessary.

► PDF of the official practical guide (DE)

► Official overview of practical guides (bienen.ch)
Note: Section Operational concept and practical guides → 1.2.1 “Liebig Dispenser”.

Summary based on Practical Guide 1.2.1 (V 2505). Last review: 01/2026.

Learn more:

• Practical Guide: 1.2.2 Nassenheider Dispenser
• Practical Guide: 1.2.5 Formic acid strips (Formicpro®)
• Apiary management: operational concept
• The recommended varroa treatment concept increases colony survival