Species of the genus Varroa are chigoe that parasitize on bees and bumblebees and cause great damage to bee colonies. The most famous species is V. destructor transmitted from Southeast Asia. It has also spread to the west where it parasitizes on the most famous species of honey bees – Apis melifera.
Females of the genus Varroa are brown in color, with a bulging back and a body that is covered with hair along its entire length. They use their oral apparatus, which is adapted for stabbing and sucking, to feed on the host’s hemolymph and thus overwinter on adult workers. Continuous feeding of small amounts of blood results in the appearance of constant sores on bees and thus can lead to infection with bacteria and viruses that are very often much more dangerous than the parasitic tick itself. Unlike females, males are milky white and do not feed.
Infected bees often show signs of infection when they try to fly in a circle, fall in front of hives or crawl on the grass, and then die quickly.
Treatments can be biological or chemical in nature, so in this post we wanted to combine parts of some of the methods in one place.
Folk treatments such as white flour, powdered sugar and even essential oils of some plants have shown some results, but all this is far from true efficiency and doesn’t provide the best protection to colony.
Varroa can be destroyed by heat at a temperature of 46 to 48 ° C. Although it was widely used in Russia, this method is less widely used today and must be performed without the presence of brood because bees die at 50 ° C. If you use this system – be very careful not to be left without the whole colony.
The installation of a mesh tray, which also serves for the diagnosis of Varroa, has an impact on the control because one part of the fallen hooves falls through the net and there is no possibility to return to the bees or the brood.
In the last ten years, there is a growing need to develop drugs that will best protect bee colonies without causing any consequences for the bees themselves.
Of the large number of drugs, barely twenty have been accepted and retained today, with none of them killing species of the genus Varroa completely. However, it is important to take certain measures in time and at the end of July or the beginning of August, when all the extensions with honey are removed, to perform the treatment against this chigoe.
When it comes to chemical treatments, fluvalinate has proven to be a tool with as much as 99% efficiency, with no negative effect on bees. However, as with most chemical treatments, resistance has emerged as species of the genus Varroa have mutated and developed resistance to this agent. The situation is similar with phenothiazine and amitraz.
Amitraz is a treatment used to fight varroa but has been found to be mutagenic in some traits in bees. It is absorbed into honey, pollen and wax and only one treatment is not enough to achieve effective results. By repeating it several times, the varroa is destroyed in a high percentage, but it leaves great consequences on the biological and immune health of bees and queens, and it is banned in the countries of the European Union.
There are 6 registered drugs in Serbia that are intended for the fight against varroa:
- Apiguard which is used as a gel twice at intervals of two weeks and is applied during the late summer period
- Apilife is a preparation based on essential oils in the form of strips that are applied four times at intervals of seven days, also used in late summer
- Furmitom is formic acid that destroys varroa and in closed litters at a temperature of 14 to 25 ° C
- Polyvar yellow is placed at the entrance to the hives in the form of sticks after pouring honey; treatment lasts at least 9 weeks
In recent years, formic and oxalic acid are highly recommended. Immersed cardboard measuring 20 x 30 x 02 cm in 20 ml of 65% formic acid is placed in the hive during the period when there are litters. If you decide on this method – be careful to meet the following conditions in order to avoid the loss of the queen: the hive flights must be 35 cm wide and the outside temperature should not exceed 30 ° C.
Based on previous data, treatments against bee chigoe must become a mandatory measure in beekeeping. After a few years, varroa leads to the destruction of the society, so you have to regularly check the conditions in the hive and keep a beekeeping diary in order to react in time.