Varroatosis or varroosis is considered one of the most serious threats to the existence of bees. For decades, beekeepers from all over the world have been unsuccessfully fighting this disease and, unfortunately, many of them have abandoned their favorite beekeeping occupation.
The Varroa jacobsoni mite is found everywhere in all regions suitable for beekeeping. The special microclimate in the hive creates all the conditions for its successful reproduction. In summer, drone brood is more affected, and larvae and pupae are affected in spring and autumn. Parasites overwinter on adult bees.
The content of the article
- 1 The causative agent and ways of its spread
- 2 How does the disease progress
- 3 Diagnostics
- 4 preventive measures
- 5 Epidemic situation
- 6 Chemical methods and methods of control
- 7 Folk methods
- 8 Zootechnical methods of struggle
- 9 Physical methods of struggle
- 10 disinfection
The causative agent and ways of its spread
The parasite is dark brown in color. It can be found directly on infected bees. The older the tick, the darker its color, and the easier it is to spot it in the hive. The parasite has a sharp piercing-sucking apparatus, with the help of which it receives bee hemolymph.
Female on bee belly
Fertilized female ticks lay eggs in cells with 8-9 day old brood. After the sealing of these cells, the full development cycle of Varroa occurs (it parasitizes on pupae).
If one mite has developed in the cell, the young bee will come out of it greatly weakened. When a larger number is parasitized, a failure occurs in the development of the larva – legs and wings do not develop, and the size of the body decreases. When six ticks “stay” in the cell, the pupa dies.
Developed female parasites crawl onto adult bees and climb into secluded places on their bodies, suitable for unhindered feeding – this is the lower part of the abdomen, the space between the legs and in the axils of the wings. Males live only on brood, where the process of reproduction and their death takes place.
Ticks prefer to colonize drones and young bees in the hive. There are much fewer of them on flying insects.
Adult female parasites live up to three months in summer and up to 8 months in winter. Up to 6-7 viable parasites can be found on bees! Bees are able to peel off varroa from each other only in separate nests. In most cases, they remain completely defenseless.
The main source of infection is infected honey bees and drones. In literally three months, Varroa can spread 6-11 kilometers, infecting all beekeeping farms in this zone.
A drone with a sucked parasite
Propagation paths:
- flight of drones on mating flights;
- contact of flying bees during honey collection (a tick falls on a flower and hides in the shade from the sun, in order to eventually “fly away” on another bee);
- attack of thief bees;
- the presence of infected apiaries on the way to the honey plants;
- rearrangement of brood frames from an infected hive to a healthy nest;
- close location of hives on the push;
- replacement of the uterus without its preliminary examination (on the uterus, Varroa is very rarely parasitized, but they can be carriers of the disease).
How does the disease progress
Varroa can be noticed only two to three years after the first invasion. During this time, the parasites colonize up to 30% of the bees – the productivity of the affected nests begins to noticeably decrease. With the rapid reproduction of Varroa, the death of families occurs in a short time.
Sizes of adult parasites
Calculating the degree of damage to the nest is quite simple:
- 10 parasites per hundred bees – a weak degree, practically not affecting productivity (the fight against the pathogen will be effective);
- 20 parasites – a moderate degree affecting performance (the prognosis of treatment depends on the measures taken);
- more than 20 – a strong nip, significantly reducing productivity and impairing the development of the family (if urgent and correct measures are not taken to eliminate the invasion, the insects will die).
Almost all breeds are susceptible to the disease! The most resistant Indian bee. But at the same time, in beekeeping practice, cases of self-recovery are not found even in this breed. The invasion must be seriously combated in any case.
In winter, the spread of Varroa slows down, especially in open-air apiaries. Low temperatures are not terrible for bees (excessive humidity is much more dangerous), but some of the Varroa females die from them safely.
As for equipped winter quarters, the situation is more complicated here. Ticks enter a warm environment, which is a prerequisite for maintaining their vitality. It is known that the most favorable conditions for Varroa are tropical and subtropical climate. And even in temperate zones, there is a connection with the spread of the invasion and weather conditions – in the summer, the infection of families increases.
Infected larva
Consequences of invasion:
- accelerated aging of the organism is observed in worker bees;
- the number of drones is decreasing;
- the fertility of the queens falls – egg-laying looks uneven, scattered over the combs;
- due to overexcitation of the uterus, egg-laying ceases very late in the autumn;
- families look weak in spring, collect honey poorly;
- in summer, heavily infected families leave old hives;
- with a strong degree of infection, a putrid odor is observed, since parasites are even in unsealed brood;
- the affected families cannot form a normal club in the autumn (in winter it loosens, cools and dies).
Diagnostics
When examining families, it is important not to be mistaken with the diagnosis. Varroa slightly resembles another pathogen – Braula, but in the latter the body is elongated in front, and the size is several times smaller. To rule out a mistake, you must contact the veterinary laboratory.
Varroa at high magnification
External signs of infection:
- drones have an ugly body shape (undeveloped wings, lack of legs, deformation of the abdomen and chest);
- worker bees fly badly, fall from the landing board, crawl on impact between the hives;
- larvae and pupae massively ejected from the nests are observed;
- the brood is always variegated – unevenly scattered over the combs (there is an interval of one or two cells).
Such symptoms require a mandatory laboratory study in order to exclude septicemia, viral paralysis and foulbrood.
preventive measures
Annual preventive examinations of nests help to identify the disease in the early stages.
Special attention is paid to drone cells. It is necessary to open the covers from several cells located in the lower part of the frame and on the frames that are extreme in the nest. Remove insects with tweezers, carefully examine them and inspect the cell itself.
This is what an unprinted cell looks like with a strong jam.
With a strong degree of infestation, Varroa are found on the bottom of hives and landing boards.
Weak infestation is extremely difficult to diagnose visually. Therefore, it is easier to perform a one-time treatment of the nests with a drug suitable for prophylaxis. At the same time, thick paper smeared with petroleum jelly is spread on the bottom of the hives. Within half an hour, you can find fallen ticks here, if they are in the hive.
Epidemic situation
If an outbreak of varroatosis is registered in the region, it is necessary to understand that distance from the focus of the disease is crucial:
- Within a radius of 7 kilometers, a quarantine is imposed, which implies a ban on the migration and rearrangement of brood from one family to another. The nests should be inspected every two weeks.
- A conditionally unfavorable zone extends within a radius of 100 kilometers. Families here are also regularly monitored for tick infestation.
Chemical methods and methods of control
None of the known chemical preparations will give a complete cure, since Varroa parasitizes in a closed brood. Therefore, physical and zootechnical methods of control must be applied simultaneously.
Treatment of varroatosis in bees is carried out with the following drugs:
Bipin is a popular and effective chemical
“Bipin” has a very high efficiency. A solution of this drug is used to treat streets in the autumn when brood is already absent. Re-processing is carried out after seven days. The dosage is 1 ml per two liters of boiled chilled water. No more than 10 ml is consumed per street.
“Varroatin” is an aerosol used at ambient temperatures between 13 and 25 degrees Celsius. To process the streets, you need to expand to two or three centimeters and spray the drug into them from a distance of 10-15 centimeters for 1,5 seconds. Aerosol is supplied to the lower entrance for 3-5 seconds.
“Thymol” crumbles in the form of a powder during the active summer at the rate of 0,25 g for each street. Re-processing is performed in a week. With a strong degree of invasion, such pollination is repeated three times with a break of four days. The use of the drug is permissible at a temperature not lower than +15 and not higher than +26 degrees Celsius. You can use the installation of the drug in bags of gauze or nylon. But if it is warmer than +26 degrees outside, the drug placed on top of the frames in bags must be removed from all families.
“Oxalic acid” it is applied in the form of irrigation. For this, 20 grams of the drug is dissolved in a liter of water and poured into a finely dispersed nebulizer. Consumption per socket: 150 ml (on average up to 12,5 ml per frame on both sides). Processing is carried out at a temperature not lower than 14 degrees. Spraying can be done four to six times per season.
“Formic acid” (or “Ant”) it is used from early spring to late autumn at air temperatures from +14 to +25 degrees. The acid is placed in open wide vials at the bottom of well-ventilated hives for a period of 3 to 5 days. Re-processing is carried out in the spring after 12 days. In the fall, the acid is set once. “Ant” is used according to the attached instructions!
Folbex it is used only in spring and summer at temperatures not lower than +12 degrees Celsius. For one family of 16-20 frames, there are two strips of the drug measuring 2 by 10 centimeters. The treated nest is closed for half an hour and then well ventilated. Re-fumigation is performed after 24 hours.
Phenothiazine do not use in the summer. In spring and autumn, processing is possible at temperatures not lower than +15 degrees. Single dose: 1,5 g of powder or 1 tablet per slot with at least three frames. The powder is introduced through the notch using a smoker with an elongated spout. In the spring, double fumigation is performed, and in the fall, fourfold fumigation with a break of one day. The tablet is set on fire and injected through a notch on an iron plate (the hive must be sealed for 40 minutes). The course of treatment is three tablets, treatment every seven to eight days.
In the spring, it is recommended to install acaricidal strips such as “Polisan”, “Fumisan”, “Apifit”, which reduce clinging and replace other chemicals.
Folk methods
Effective folk remedies are:
- a decoction of wormwood and pine;
- chopped thyme herb.
Blooming thyme (thyme)
Thyme herb it is used before honey pumping – the last processing is carried out seven days before the bee products are received. It is necessary to pass 100 grams of grass through a meat grinder, place between two layers of gauze on the upper part of the frames and cover with plastic wrap. After three days, the old thyme is replaced with fresh one.
Wormwood and pine decoction issued at the end of the season as a medical supplement. It is prepared as follows: 50 grams of pine buds and 900 grams of fresh wormwood with flowers is boiled in ten liters of water for two to three hours. Then 30-35 ml of broth is added to a liter of syrup. The received medication is dispensed at the rate of 10-12 liters per family.
How are folk remedies used in the treatment of bees
Zootechnical methods of struggle
These methods are suitable as non-drug treatment and prevention:
- the formation of layering without brood is performed;
- the destruction of parasites is carried out at the expense of drone brood (they prefer this brood most of all, since there is a lower temperature and a larger cell volume) – this technique is especially effective in areas where egg-laying after the end of drone rearing lasts a short time;
- the drone brood is left in the least infected families with high productivity – it is used for insemination of young queens;
- the nests are equipped with nadal traps and stretchers, which do not allow fallen Varroa to climb onto the bees again – such a stand has a height of 5-6 cm and a metal mesh around the entire perimeter with a mesh diameter of 2-3 mm;
- to expand the nests, fresh honeycombs or honeycombs are installed that have been used for no more than 2-3 years;
- honeycombs used in beekeeping are renewed annually (by 30-40%);
- hives are installed in sunny places, and their bottom rises above ground level by no less than 30-40 centimeters.
Important: frames with opened drone cells must be immersed for 10-12 hours in a 2-3% solution of acetic acid. After that, the larvae are shaken out, and the combs are washed with clean water and dried.
Physical methods of struggle
This technique implies, first of all, use of thermal chambersconsisting of a cassette for bees, a funnel and a separate compartment with a heating element. The camera is made of plywood or wood. Its height (per cassette) is 1,2 meters, and its width is 75 cm. A pull-out tray made of metal mesh with a cell of 45 by 0,5 mm is mounted 0,5 cm from the bottom. Ticks will gather here.
Thermal chamber in section
At a temperature of only 48 degrees, parasites die in 15-18 minutes (their bodies lose moisture faster than bees). Shaking or rotating the cassette (the mechanism of action depends on the camera model) crumbles the Varroas into the pallet. Bees are planted for treatment without a queen in order to exclude club formation and steaming.
New methods include the use of special frames equipped with plastic honeycombs.… They are painted bright green by the manufacturer to simplify the work of the beekeeper. This device has a cell size that allows the queens to lay only unfertilized eggs.
After 8-10 days, such frames are removed from the nest along with the ticks that have populated them, wrapped in a plastic bag and sent to the freezer overnight. In the morning, the frames are cleaned, disinfected and returned to their place. You can buy them online.
disinfection
Treatment of bees for varroatosis is carried out simultaneously with disinfection measures.
The combs and frames suitable for further use are cleaned and placed in tightly closed boxes. A rag moistened with an 80% solution of acetic acid is placed on top. Consumption: 200 ml of solution for 10-12 frames. Disinfection by this method takes 3-5 days, depending on the air temperature – the lower it is, the longer the mites are destroyed. After processing, the honeycomb is ventilated during the day.
The hives and their wooden parts are disinfected by the flame of a gas burner or blowtorch.
The downloaded honey can be used for food without restrictions, but it is not suitable for feeding bees.
Important: therapeutic, preventive and other measures are carried out in the spring after the spring cleaning flight, and in the summer-autumn period immediately after honey pumping or before the formation of a winter club.
