Many things has been tested in the fight aginst Varroa destructor. Organic acids have shown reasonably good results and and have been used for more than 10 years in Europe. The first acid used was Formic acid that was evaporated at a slow speed inside the hive. It is still in use when it's the only acid that penetrates the wax and kill mites inside the capped cells. It does have some drawbacks when it depends on several factors like temperature, hive volume and hive type, and has to be monitored carefully for efficiancy.

Lately Oxalic acid has proven to be useful, research is going on in a number of countries in Europe and is coordinated to compare results from different regions.

Trickling a solution of water-sugar-oxalic acid is a promising method to keep Varroa levels down.

It has to be done late in the season when there is no brood in the hive.

A large syringe makes it easy to control the volume given to each hive.

It is much faster, safer, and cheaper than using a vaporiser.

Use only Oxalic-2-hydrate (C2H2O2*2H2O), not the waterfree Oxalic.

Mix 7,5 parts Oxalic to 100 parts water and 100 parts sugar by weight

75 g Oxalic-1 liter water- 1 kg sugar will make 1,66 liter solution that is enough for 50 hives. This mixed up solution will keep for a few weeks only and should be used at once.

Use 20 to 35 ml solution for each hive depending on the size of the treated colony.

On a 2 box hive the solution is distributed according to the amount of bees in each box. The top box normally holds more bees and is given 70% of the solution.

The bottom box is given 30% of the total solution.

The solution is distributed evenly in the gap between the top bars, so it will drip down and reach as many bees as possible.

Time per hive 1,5 min. Cost per hive 0,1 €.