Oxalic acid calculator: how much should you trickle?
Enter the dose per seam from the product leaflet, the number of seams of bees and the number of hives, and see how much solution to mix.
The dose depends on the product and is stated on the leaflet. Always respect the product's maximum per colony. Trickle only once per winter, when the colony is broodless.
How to use the calculator
Oxalic acid is dosed per seam of bees, not per hive. Count the seams between the frames where bees are sitting when you lift the crown board. A normal winter colony in a single brood box covers 6 to 10 seams. The dose per seam is on the leaflet for the product you use and varies between products, so always follow it. The calculator multiplies the dose by seams and hives and adds 10 percent for spillage.
When and how
- Trickle when the colony is broodless, usually in December, 2 to 3 weeks after the first cold spell.
- Pick a day above freezing, ideally 2 to 8 degrees, when the cluster is sitting quietly.
- The solution may be lukewarm. It makes the bees less unsettled.
- Trickle directly onto the bees in each seam with a syringe or dosing bottle. Not onto empty seams.
- Close up straight away. Put in a clean floor insert and count the mite drop after a week.
- Record the treatment with date, hive, product, dose and batch number.
What should drop?
Fewer than 200 mites in the drop after trickling is considered low. If many thousands fall, the colony was heavily infested, so start early with drone frames in April and count again in early summer.
Oxalic acid treatment: the full guide ›
Frequently asked questions
How much oxalic acid does a colony need?
It depends on the product. The dose per seam is on the leaflet, and a colony on 8 seams gets 8 times that dose. Respect the product's maximum per colony.
Can I trickle twice?
No. Repeated trickling close together harms the bees more than the mites. One treatment per winter, when the colony is broodless.
What if the colony is not broodless?
Wait a couple of weeks, or treat anyway and accept a lower effect. Wax cappings in lines on the floor insert mean brood is still emerging.