Information provided by: Bee Research Institute DOL, 252 66 Libcice, Czech Republic

FORMIDOL - pad soaked in formic acid for the varroa mites control

Content: 40 ml 85% formic acid in one pad        

CAUSTIC SUBSTANCE!         Use Gloves!                   Apply only as directed!


Description and function

The evaporation pad, dimensions 250 x 187 x 1.2 mm, is in a wrap with five holes, diameter of each is 20 mm. Holes are directly on the pad surface and regulate the starting evaporation which is most intensive right after the insertion. The pad twists while drying. Edges of the holes get separated from the pad and the evaporation is increased again. This regulation provides an effective concentration of the formic acid during two days. The third day (48 hours after the insertion) the wrap is removed and the rest of the acid may evaporate. The evaporation pad acts in two phases. In the first phase - which lasts usually 48 hours - the acid evaporates only through five holes of the wrap. The concentration of the acid vapors is sufficient for the control of the development stages of mites in the brood cells. Simultaneously we may observe the fall of adult mites. The regulation wrap reduces the disturbance of the colony at the beginning of the evaporation which otherwise might lead to the loss of the queen. In the second phase after the removal of the wrap a rapid evaporation of the rest of the acid sets in. For a short period of time the increased concentration of vapor results in the further fall of adult mites.

Application time

FORMIDOL pad with formic acid is intended for the summer treatment of colonies after the honey harvest. If maximum temperatures exceed 25deg. C, do not insert the pad or remove the wrap during midday when the temperature is high. Do it in the morning or in the evening after the colonies are settled.

Insertion of the FORMIDOL pad into the hive

Take off the outer wrap, keep in place the inner wrap with the five holes. The side with the holes is marked by a ring. The pad is inserted on the bottom board under the combs with the sealed brood. The distance between the lower bars and the pad should not be larger than 1 to 2 cm. The holes are directed upwards. The hive entrance is left open.

Alternatively, the pad may be placed between the brood chamber and the honey super. Position the pad to provide a free space under the holes.

Make sure that the inner wrap is not damaged and it sits tightly on the pad.

After 48 hours (see also Recommendations) take the pad out, remove the inner wrap and return the pad back into the hive. After further 48 hours remove the pad from the hive. Otherwise the bees will start to bite the pad and carry it out from the hive.

Effectiveness and number of treatments

After one treatment of the FORMIDOL pad we can achieve on average a reduction of the mite population to about a half. At lower infestation this is sufficient for the protection of the winter bee generation before the regular fall treatment. At higher infestation we can insert another pad 5 -8 days after the removal of the first pad. The repeated treatment is recommended also for strong colonies.

The formic acid acts not only against varroa but also against chalk brood and nosema disease.

The risk of the injury to honeybees

If the instructions are followed, the harm to honeybees is negligible. In the most cases the increased buzzing and activity after the insertion of pads will cease after 15-20 min.

In individual cases injuries on small number of drones, just emerged bees, and brood before the emergence may be observed. The loss of the queen is rare.

The possible damage represents no serious danger to the hive during the season recommended for the application. The most effective concentration borders on the damage limit of bees.


Since the rate of evaporation is influenced by the behavior of bees and by the hive type, we recommend testing the pads in a few hives before the mass treatment. If the excitement of the bee colony is too high (a part of bees leaves the hive, larger number of dead bees or dead pupae drop on the hive bottom), one or two holes may be covered to reduce the rate of evaporation. In that case leave the inner wrap on for one or two more days.

Extend the time before the removal of the wrap if the weather is cold and moist during the first days after the insertion.

The basic dose (5 holes in the first phase, removal of the inner wrap after 48 hours) is intended for a honeybee colony in two boxes.

Safety of bee products

This application of the formic acid is considered safe to the bee products and environmentally friendly.