Amitraz is a low-cost and highly effective way to control varroa mites in bee hives if used correctly. This note describes a method that has worked well for me.
Paper Towel Method
- Mix 2 ml or 3 ml 12.5% Amitraz with 4 of 5 ml cooking oil in a plastic bag large enough to receive the paper towels.
- When the liquid is mixed, add the paper towels into the bag and allow them to soak up the liquid.
- Treat hives shortly after mixing, as the chemical degrades rapidly.
- Place one rolled-up paper towel (containing 2-3 ml Amitraz and 4-5 ml oil) across the top bars in the middle of the brood nest.
- Repeat the treatment after two weeks and again after four weeks.
Approximately half the mites in a hive are in sealed brood cells and Amitraz does not kill those.
Thus the 2nd and 3rd applications are important as the Amitraz is only effective for a few days.
The 2nd and 3rd applications are needed to kill those mites after they emerge from the brood cells.
1) Estimate mite loads using a soap wash on a sample of hives before treatment and again after treatment. Soap washes before treating will confirm the need for treatment. Soap washes after treatment measures its effectiveness.
2) Treat every hive in an apiary at the same time, so there are fewer drifting bees re-introducing mites to the hive.
3) When working with Amitraz, wear eye protection and avoid Amitraz contact with skin. Nitrile gloves provide good protection.
4) Use the dosage described on the Amitraz instructions. Do not overdose.
At the time the Amitraz label was designed for Fiji, more than one year ago, treatment had been tested only using strips of wood with a specific amounts of Amitraz soaked into each one.
Two ml of 12.5% Amitraz proved effective in killing mites with no adverse affect on the bees’ breeding or behaviour.
Since then, further research suggested that mixing Amitraz with cooking oil preserved the effectiveness of Amitraz in the hive, and soaking it into paper towels instead of wood strips allowed the bees to remove it from the hive.
Paper towels are also more readily available than wood strips.
Thus this update.