Tick varroa - the causative agent of a dangerous disease of bees and a carrier of various infections, is widespread throughout the world. We will talk more about the features of the development of the pest, the methods and symptoms of infection, the measures for controlling and preventing it later in the article.
Description and life cycle
The tick of Varroa Jacobsoni refers to ectoparasites living on bees. It has a very flat body, similar to an inverted oval saucer with protruding lower limbs covered with hairs. Four pairs of tick legs allow it to crawl and help to stay on the bee.
The body of the female is transversely oval in shape of brown or dark brown in size, 1.6-2 mm in size. It can be seen with the naked eye. The oral apparatus is a piercing-sucking type and is usually hidden under the body. With its help, the female punctures the bee integument from chitin and feeds on the hemolymph of the blood of adult insects, larvae and pupae.
Of the specific morphological features of female varroa, the following can be distinguished:
- the presence of the movable part of the peritremal tube, which allows you to regulate breathing in various conditions of existence;
- a peculiar body shape, which provides reliable fixation of the tick on the bee's body;
- the presence of small teeth on the chelicera, directed back, which keep the females from falling out of the wound on the body of the host;
- springy cover of the body, preventing the adherence of the insect during their life in the bee brood.
The male is smaller and almost round (about 0.8 mm in diameter), visible only in bee brood. His body has a grayish white or light yellow hue. The pharynx is devoid of powerful muscles and is hardly visible. The oral apparatus serves only to transmit the seed during the fertilization of the female. There are suction cups at the end of the legs.
The life cycle of the development of the tick of varroa consists of the following stages:
- A mite tick (adult female) gets from a working bee or from a drone onto a honeycomb.
- The tick gets into the cell with the larva on the eve of its sealing. Often this happens in a drone brood, but possibly in a bee.
- After the cell is sealed (after three days), the female tick begins to lay eggs (on average 1 egg per day, only about 5 pieces). The length of the egg is 0.5 mm. A larva develops in it, which turns into a nymph with four pairs of limbs.
- A nymph (protonymph) emerges from an egg 0.7 mm in size.
- After a one-time molt, the next stage occurs - the deutonymph. The dimensions of the female are 1.3 per 1 mm, the male - 0.7 mm in diameter. The chitinous shell is quite soft whitish. They feed on hemolymph.
- Being in the cell, the male fertilizes young females, after which he dies of hunger. Therefore, on adult bees, only female ticks can be seen.
- After the young bee has completed its development, it leaves the cell. Ticks, including an adult female, also get over with her. They climb bees (drones and working bees) and remain on them until the next egg laying. Each female tick is able to lay eggs several times. Young females have a lighter shade of chitinous shell than adults. Only a few days later it gradually darkens.
The entire development cycle, from egg laying to an adult tick, has a duration of:
- at the female - 8-11 days;
- the male - 8-9 days.
In summer, the female lives for 2-3 months, and in winter - about 5 months. In the winter season, due to the lack of brood, varroa cease to breed and 7-10% of them die.
In early spring, with the advent of brood and during the summer, the number of ticks in the bee family increases by about 20 times. In autumn, when their numbers in the bee family decrease, pests switch to uninfected bees.
Females of varroa retain their viability outside the bee family:
- in empty hives on combs - 6-7 days;
- on the corpses of a bee / drone - 3-5 days;
- on pupae - 7-11 days;
- in wax-pepper crumb - 9 days;
- on honey plants - 1.5-5 days;
- in a sealed brood - 30 days;
- in open brood - 15 days.
Females can starve at a temperature of 22-25 ° C for 5-6 days. At low external temperatures or the presence of harmful substances in the air, the tick stops breathing and hides in the cell of the honeycomb, thereby making it difficult to take measures to combat it.
As a rule, up to 5 ticks are attached to one working individual, 7-8 females to drones, 12 and 20 respectively to pupae of working bees and drones. Location of parasites:
- between the first and second segments of the abdomen;
- between thoracic segments;
- in the joints of the chest and head, chest and abdomen.
Unhindered reproduction of varroa leads to the death of the bee family in 2-5 years. The more ticks in the hive, the sooner the family dies.
The parasite develops well in weak families and old honeycombs of a dark brown color.
Methods of infection
Varroa Jacobsoni provokes a severe invasive disease of larvae, pupae and adult bees, called varroatosis. This disease is one of the most urgent problems of beekeeping and causes him tremendous damage.
In the summer, the tick spreads from sick bees to healthy through:
- wandering bees;
- thief bees;
- with apiary migrations;
- bee-standing families;
- with swarms;
- when buying and selling bees and queens;
- when families are infected with brood;
- upon contact of bees on the flowers of plants;
- with all work on the rearrangement of cells from one family to another;
- from other insects (bumblebees, wasps);
- at open storage of the cut drone brood.
Varroatosis spreads at a speed of 6-11 km for 3 months, which depends on the degree of saturation of the region with bees. First of all, affected families are affected.
The distribution and growth of pests is significantly higher in areas with a hot climate.
In addition to the defeat of varroatosis, varroa is dangerous for its ability to carry infectious diseases of bees (American foulbrood, nosematosis, paratyphoid, etc.). Mixed diseases accelerate the course of the disease and lead to mass death of bees.
Signs of infection
The first 2 years the disease develops unnoticed. Then a large number of ticks appear (especially in the summer), which affect up to 30% of bees. Bees and drones have characteristic flaws:
- lack or defective development of legs and wings;
- body deformation;
- brood has a variegated color.
Other signs:
- The losses of bees increase sharply, mainly in October-November. During this period, infection increases several times.
- In the autumn-winter time, the bees are quickly depleted, as a result of the family they die or leave the wintering very weak.
- During wintering, the bees behave very restlessly - they make noise, jump out.
- The bottom of the hives is covered with dead bees, on which brown mites can be seen.
- With a high degree of varroatosis damage, mortality of bee colonies begins in the first half of wintering.
- After the main gathering of honey, upon returning from a nomad, strongly infected families leave their hives. They do not stop even a sufficient amount of feed.
Methods of struggle
To combat ticks, a whole range of measures should be carried out, which includes organizational, special beekeeping and veterinary measures. It is necessary to observe the conditions of keeping, feeding, breeding bees, as well as apply zootechnical techniques to combat varroa and systematically carry out anti-acaricidal treatments.
Pest control should continue annually and comprehensively.
It is very important to reduce the number of ticks after the last pumping of honey. So the bees that hatch and will winter will be able to live with a minimum level of infection. At the same time, the degree of stress decreases when feeding bees. The following treatment will be most effective after the end of brood breeding (in winter). In the spring, to reduce the number of pests, the drone brood cutting method is used.
Conventionally, measures to combat these parasites can be divided into 2 groups.
Medication
When using chemicals, you should adhere to the main recommendations:
- It is forbidden to use drugs before or in the process of collecting honey. In many regions, spring treatment is associated with risk, as honey collection often starts earlier than planned. As a result, chemical residues remain in honey.
- Use exclusively authorized medicines (non-compliance with this rule is punishable by quality control authorities and is determined by diagnosing bee products for the presence of drug residues in them). For example, formic acid can only be used in the form of an Illert tile, even though other forms are more effective and better tolerated by bees.
- Before use, it is imperative to carefully read the instructions.
- Honeycombs that are in the hive during processing (except for the treatment with formic acid) cannot be used in the form of honey cells. They need to melt as soon as possible.
- During pumping, it is imperative to separate the wax particles (through a sieve, gauze) from the honey, as medicines may enter it.
On the eve of each treatment, the beehive is placed in a pan, resorting to two options:
- through a hinged lid on the back, or a large opening;
- lifting the lower case (the bees begin to worry at the same time).
But, the mesh bottom under which the pallet is placed is the most suitable option. During the control of such a pallet, the bees remain calm. You must try not to disturb the bees at all before processing.
Chemicals are used that destroy or severely damage ticks. Medicines evaporate in the hive, feed to bees and work through their blood. It is also possible that the bees come into contact with the medication (through the strips along which they crawl).
Consider some of the acceptable medications.
1 Pericin
The action of this drug is carried out through the blood and is aimed at parasites that are not in the brood, but directly on the bees. Use it should be exclusively in a barren winter time (twice with a break per week, if not combined with additional medications). Use is admissible at 0 ° C or at a small subzero temperature.
Pericin is fat-soluble, so its particles remain in wax and honey.
Consumption:
- for a family in two buildings - 25-30 ml of an emulsion;
- in one case (or layers) - 20 ml.
The amount depends on the size of the family, but most often the recommended dosage in the instructions for 50 ml is too much. Bees can be treated with pericin solution using either a special dosage kit or a disposable syringe.
2Apitol
This drug is water soluble and easily penetrates into honey, so proceed with caution.
It is strictly forbidden to combine apitol with food and use it in the feeding process.
This tool should be resorted to in the case when ticks have developed resistance to previously used drugs. Processing is carried out at low air temperature in a barren time. Apitol goes on sale in the form of a powder, which must be dissolved in a large amount of liquid.
3Formic acid on the Illert tile
The method is based on the evaporation from the tile surface of formic acid, which then penetrates the mites with the air entering the hive, thereby externally acting on them. It is necessary to use the drug in the evening with an open notch, at an air temperature in the range + 12 ... + 20 ° С.
It is forbidden to use the drug during honey collection.
If you do not combine this method with others, the processing frequency will be 3-4 times with interruptions in a couple of weeks.
Before treatment with formic acid, it is necessary to clean the wax bridges from the upper planks of the frames. Then you should blow smoke over the honeycomb so that the uterus is below. In the hives, one tile is placed on the frame per tile, in two-hull - two. Then the hive is closed. With excessive thickness of the tiles, an empty extension is placed on top.
A negative effect is possible - there is a risk of uterine loss.
When working with Illert tiles and formic acid, waterproof gloves and goggles must be worn.
4Cecafix
The use of this tool is similar to pericin. However, the advantage of cefix is that it is better tolerated by bees.
5 Bayvarol
The tool is a special strip that is hung around the perimeter of the central span between the combs (4 pieces per family in two-hive hives). Contact with bees occurs in close contact with the strips. The manufacturer recommends leaving the bayvarol for 6 weeks, however, this can lead to excessive concentration of the drug in the wax. Therefore, the optimal period of stay of the strips in the hives is 3 weeks.
Work should be carried out with gloves. It is necessary to take care of the proper disposal of baivarol, since it is forbidden to throw strips into garbage or into water bodies.
Biotechnical
The essence of these methods is that the beekeeper intervenes in the course of their biological development in order to destroy ticks. These include:
- Drone brood cutting - certain honeycombs with a printed brood (drone brood) are destroyed, where the female ticks lay their eggs. As a rule, for this, the drone brood is frozen. The application of this method should begin in late March - early April.
- Destruction of the honeycomb trap with a womb locked in it. The uterus is thrice alternately planted for 10 days on an empty honeycomb in a frame cage. Thus, the uterus worms inside the cell. For 10 days, outside the cell with the uterus, there is no open brood left, and ticks for the purpose of reproduction are moved to the open brood of the honeycomb trap. This brood is destroyed (it is frozen).
- Heat treatment honeycomb traps or all honeycombs with brood - heating occurs to a temperature harmful to ticks, but acceptable for bees. This method is effective but time consuming.
Medical and biotechnological methods of control can be successfully used in combination. Their combination will help to keep the number of ticks at a harmless level and will compensate for the shortcomings of individual methods. Wherein:
- the number of medicines used is reduced;
- the content of chemical residues in wax and honey is reduced;
- the number of ticks is reduced to an acceptable value.
Each beekeeper should consider his pest control strategy, which will depend on the design features of his beehives, technology for keeping bees, climate and food supply.
Preventive measures
To reduce the damage caused by the tick of varroa, various preventive measures should be taken:
- Acquired families and captured swarms must be processed at least once (for example, a swarm with pericin, and the rest with formic acid). Based on the number of parasites on the pallet, a decision is made on the need for further processing.
- Regular examinations of the sump and drone brood should be carried out for the presence of parasites.
- Treatment against varroatosis is extremely important to coordinate with neighboring beekeeping farms to obtain a good result and to avoid re-infection.
- Apply methods of control regularly, do not miss the periods most suitable for their implementation.
- Periodic cleaning and disinfection is mandatory. Compliance with the usual rules of hygiene will protect against mixed diseases.
- It is necessary to reheat cells in a timely manner.
The features of the varroa tick, the analysis of tackiness on larvae and adult bees, methods of treatment, drugs for pest control and the time of their use are described in detail in the video:
Varroa mites are dangerous pests that provoke a deadly disease that causes serious complications in the apiary. However, today there are a large number of ways both to combat attacking parasites, and to prevent their appearance and spread.