Sacbrood: signs, photos, treatments, reviews

Content

1 What kind of disease is Sacbrood?
2 Possible causes of infection
3 Signs of bee brood disease
- 3.1 How to diagnose sacbrood in bees
4 Sac brood of bees: treatment
5 Disinfection of hives and equipment
6 Prevention methods
7 Conclusion

Sacbrood is an infectious disease that kills bee larvae and young pupae. In Russia, this infection is quite widespread and causes economic damage, causing the death of bee colonies. In order to stop bee brood diseases in time, you need to see their signs as early as possible (for example, in the photo), learn methods of treatment and prevention.

What kind of disease is Sacbrood?

The name of the disease "Sac brood" comes from the appearance of the diseased larvae. When infected, they become like sacs filled with fluid. The causative agent of this disease is a neurotropic virus.

It affects the larvae of printed brood of honey bees, drones, and queens of all breeds. Young larvae that are 1 to 3 days old are most susceptible to the disease. The incubation period of the virus is 5-6 days. Prepupae die at the age of 8-9 days before being sealed.

Bee brood disease occurs after a virus enters the body, which is very resistant to various types of physical and chemical influences:

drying;
chloroform;
3% caustic alkali solution;
1% solution of rivanol and potassium permanganate.

The virus remains viable while:

on honeycombs – up to 3 months;
in honey at room temperature – up to 1 month;
when boiling – up to 10 minutes;
under direct sunlight - up to 4-7 hours.

Due to the death of the larvae, the bee colony weakens, the productivity of the honey plant decreases, and in severe cases, the colonies die. Adult bees carry the disease in a latent form and are carriers of the virus in the winter season.

Sac brood appears in central Russia in early June. In the Southern regions a little earlier - in May. During the abundant summer honey production, the disease subsides or completely disappears. It may seem that the bees themselves coped with the virus. But in early August or next spring, the untreated disease manifests itself with renewed vigor.

Possible causes of infection

The carriers of the infection are considered to be adult bees, in whose bodies the virus persists throughout the winter. Various insects can transmit the virus:

within the family, the disease is spread by worker bees, which, while cleaning the hives and removing the corpses of infected larvae from them, become infected themselves, and when feeding healthy larvae with food, they transmit the disease;
Varroa mites can also bring the disease – it was from them that the sacbrood virus was isolated;
Thieving bees and wandering bees can become a source of infection;
untreated work equipment, honeycombs, drinking bowls, and feeders may also contain infection.

Infected worker bees most often spread the virus between colonies in the apiary. The spread of infection occurs during raids or can occur when moving honeycombs from sick bees to healthy ones.

Signs of bee brood disease

The incubation period for the development of infection lasts 5-6 days, after which you can easily notice signs of sac brood, as in the photo, by examining the honeycombs:

the lids are opened or perforated;
the honeycombs have a variegated appearance due to the alternation of sealed cells with empty ones;
the larvae look flabby and watery in the form of sacs;
the corpses of the larvae are located along the cell and they lie on the dorsal side;
if the larvae have already dried, they have the appearance of a brown crust with the front part bent upward.

Externally, honeycombs with affected brood resemble foulbrood disease. The difference is that with sac brood there is no rotten smell and no stringy mass when removing corpses. Also, with sacbrood, the infection spreads more slowly than with foulbrood. In the first summer, 10 to 20% of families may become ill. If the disease is not treated, then in the second summer up to 50% of the bees in the apiary may be affected.

In a strong colony, bees throw away dead brood. A sign of a weakened family - the untouched corpses of the larvae are left to dry in the cells. The degree of damage by sacbrood is determined by the number of dead larvae in the combs.

Important! Beekeepers have noted that sick foraging bees are not as productive as healthy ones, and their life expectancy is reduced.

How to diagnose sacbrood in bees

Bees can suffer from several diseases at once, including sacbrood, which shares symptoms with American and European foulbrood. In this case, clear signs of this disease are not easy to detect. To dispel all doubts, a sample of honeycomb measuring 10x15 cm is sent to the laboratory for analysis.

Currently, there are many methods for laboratory diagnosis of viral diseases of bees:

linked immunosorbent assay;
polymerase chain reaction (PCR);
chemiluminescence method and others.

All of them have a number of disadvantages for detecting strains of the same virus. The polymerase chain reaction is considered the most accurate.

The analysis results are ready in 10 days. If the disease is confirmed, the apiary is quarantined. If up to 30% of the bees are sick, the beekeeper separates the sick colonies from the healthy ones and takes them to a distance of about 5 km, thus organizing an isolation ward.

When more than 30% are found infected with sacbrood, an isolation ward is set up in the apiary, and all families receive the same feeding.

Attention! An accurate diagnosis can only be made in a special laboratory after testing.

Sac brood of bees: treatment

If an infection is detected, the apiary is closed for quarantine. Treatment of sacbrood is carried out only for weakly and moderately damaged colonies. Families with severe damage are destroyed. Before starting the treatment itself, several measures are taken to improve the health of the sick family:

Frames containing brood from healthy colonies are added to infected hives.
They replace sick uteruses with healthy ones.
They insulate hives well and provide bees with food.

Also, for strengthening, two or more sick families are united together. Treatment should be carried out in disinfected hives, from which frames with a large amount of diseased brood are removed.

There is no cure for infection as such. Remedies used to treat sick bees with sac brood only weaken the signs of illness in bees.In the first half of summer, individuals infected with sacbrood are fed with sugar syrup with the addition of Levomycetin or Biomycin (50 ml per 1 liter of syrup).

According to beekeepers, treatment of sacbrood can be carried out using the Endoglukin aerosol. Spraying is carried out 3-5 times every 5-7 days. The air temperature should be within +15… +22⁰WITH.

An effective way to combat the spread of sacbrood is considered to be a temporary (1 week) cessation of egg laying. To do this, the queen of the hive is removed, and a barren queen is planted in her place.

Warning! Quarantine from the apiary is removed a year after all bees have fully recovered.

Disinfection of hives and equipment

Sanitary treatment for sac brood of wooden objects, including beehives, is carried out as follows:

Spray with 4% hydrogen peroxide solution (0.5 l per m²).
After 3 hours, wash with water.
Dry for at least 5 hours.

After this, new bee families can be populated in the hives, and the wooden equipment can be used for its intended purpose.

The remaining accessories used when working in the apiary undergo the same disinfection as for foulbrood disease:

honeycombs from diseased hives are reheated at t 70⁰C or disinfected with steam of 1% formaldehyde solution (100 ml per 1 m³), after which it is ventilated for 2 days and only then used;
honeycombs can be treated with a 3% solution of hydrogen peroxide, irrigating until the cells are completely filled, shaken, rinsed with water and dried;
towels, dressing gowns, canvases from the hive are disinfected by boiling for half an hour in a 3% solution of soda ash;
face nets are boiled for 2 hours in a 1% solution of hydrogen peroxide or 0.5 hours using the drug “Vetsan-1”;
metal equipment is treated with 10% hydrogen peroxide and 3% acetic or formic acid 3 times every hour.

One of the simple and effective methods of disinfection is considered to be treatment with a blowtorch.

The plot of land on which there were hives with colonies infected with sacbrood is treated with bleach at the rate of 1 kg of lime per 1 m²by digging to a depth of 5 cm. Then apply abundant watering of the area with water.

Prevention methods

It has been noted that the greatest distribution of sacbrood occurs in cool, damp weather, in weak bee colonies, in poorly insulated hives with insufficient nutrition. Therefore, to prevent the appearance and spread of bee brood disease, it is necessary to create certain conditions in the apiary:

maintaining only strong families;
sufficient supply of food;
complete protein and vitamin supplement;
timely updating and insulation of the hive, good maintenance;
mandatory check of the hive in the spring, especially in damp, cool weather;
location of bee houses in dry, well-lit places;
regular cleaning and disinfection of beekeeping equipment every spring after the bees overwinter.

It is necessary to inspect the hive at least once every 2 weeks. At the first sign of sacbrood, all measures must be taken to ensure that other bees remain healthy.

Conclusion

Sacbrood cannot be cured permanently, since an exact treatment method has not yet been developed. Three-time use of the recommended drugs with an interval of 7 days only removes the clinical signs of the disease.The virus remains in the family as long as there is a varroa mite, the main carrier of the virus. However, creating favorable conditions for the formation of strong bee colonies reduces the risk of the spread of sacbrood.

Bee brood diseases