Honey Bee Diseases and Parasites
Like us honey bees have many diseases and parasites that affect the survival and development of the colonies. We can classify the diseases as brood diseases and adult bee diseases. The most common brood diseases are:
- American Foulbrood Disease (AFB): Bacterial disease (Paenibacillus larvae )
- European Foulbrood Disease (EFB): Bacterial disease (Melissococcus pluton. Bacterium eurydice, Bacillus alvei, Bacillus laterasporus, Enterococcus faecalis).
- Chalkbrood disease: Fungus disase (Ascosphaera apis)
- Stonebrood disease: Fungus disease (Aspergillus flavus)
- Sacbrood disease: Virus disease (Sacbrood virus)
Adult bee diseases
- Nosema disease: Protozoan disease (Nosema apis, Nosema ceranae)
- Septicemia: Bacterial disease (Pseudomonas apiseptica)
- Chronic bee paralysis : Virus disease (Chronic bee paralysis virus)
- Acute bee paralysis: Virus disease (Acute bee paralysis virus)
- Deformed wing virus disease: Virus disease
Most common parasites
- Varroa mite (Varroa destructor)
- Tracheal mite (Acarapis woodi)
- Small hive beetle (SHB)
- Asian bee mites: Tropilaelaps clerae and Tropilaelaps mercedesae
- Phorid flies or Zombie flies
Most common pests
- Wax moth
- Bee eater (Merops spp)
I will describe all these diseases and parasites, describe the symptoms and diagnosis of the diseases and discuss the treatment and control methods.
Honey bee diseases and the parasites especially the brood diseases and the Varroa mite are the biggest problem of the world beekeeping. The government and the beekeepers have responsibilities to prevent the spread of diseases.
Federal Bee Law (The Honeybee Act) passed in 1922, restricted importation of living adult honeybees into the USA. All 50 states have specific laws dealing with the diseases, registration, parasitic mites and Africanized honey bees.
Regardless of the colony numbers all the beekeepers must develop a bee disease management program. The first requirement is to learn the diagnosis of bee diseases and parasites. If the beekeepers do not know the diseases symptoms they cannot take the corrective action and lose their colonies and contaminate the area with the pathogens.
Second requirement is the periodic colony inspections. I advise to inspect the colonies every 10 days in Africanized states and every 2-3 weeks in other states. Beekeepers should know the strength and the condition of their colonies. Experienced beekeepers can tell if there are any problems by just walking in front of the hives and looking at the flight activity.
- If the flight activity is not usual check these colonies first.
- The presence of many dead bees in front of the hives is an indication of pesticide kills or robbing activity.
- If the colonies are robbed you will see hundreds of bees trying to enter the hive from the hive entrances, between the supers and all around the hive where they can enter. Hive bees fight with the robber bees and you will see many dead bees in front of the hive. There is usually wax particles or debris on the flight board and the hive entrance gets darker. You will also notice these darker markings on the joints of the supers or any openings where the robber bees entered. Beekeepers should be able to differentiate the robbing behavior and normal flight activity.
- Quickly check the weight of the colonies by lifting the hives. If they are light, either they are short in honey, they starved to death, robbed or absconded.
- Check these abnormal looking colonies first. If they are dead, or robbed remove the hive from the apiary, clean the hive and recycle the combs if they are reusable. If there is any disease, treat the colonies.
During inspection, check for the queen first.
- Look at the performance of the queen. If the brood pattern is good and if you see eggs and larvae in the cells the queen is present. If there is no eggs or no open brood, and if there are queen cells, the queen died or killed and the colony is rearing new queens. If you see emerged queen cells, and no open brood, there is most likely a virgin queen in the hive. If there is no brood, there are many small size drones and multiple eggs in the cells, the colony is queenless for a long time and it became a laying worker colony. If the laying worker colony is very small you can shake the bees and give the combs to other colonies. If the colony is still strong you can give a frame of young brood and eggs, they will rear a new queen.
- While inspecting the colony ask these questions
- Are there eggs, larvae and pupae? If yes, queen is present
- Is the brood pattern good and solid? If yes, the queen is good, young and prolific
- Does the brood look healthy? Look at the color of the sealed brood. They should be healthy looking
- Are there any holes on the cappings? There is most likely brood disease (AFB)
- Look at the color of the larvae in the open cells. Are there any yellowish, brownish or black larvae? If yes there is EFB disease
- Look at the cappings of sealed brood. Are there any sunken, brownish, greasy looking cappings or holes on the cappings? If yes you have AFB problem
- Is there any abnormal smell like rotten meat or sour wood glue smell? If yes you have AFB and/or EFB disease.
- Look at the adult bees
- Are there any wingless or deformed winged workers and drones? If yes you have a serious Varroa mite problem. It might be difficult to save the colony.
- Look at the honey combs. Are there any beetles, beetle larvae on the corners or on the bottom board, and/or slimy honey? If yes you have a serious SHB problem
- Look at the inside and the outside of the hive, and hive entrance. Are there any feces? You probably have a nosema disease.
- Are the bees clustered and can not move or fly? They are starving and will dye soon. Give them one or two frames of honey and start feeding them. It is better to scrape the honey with a hive tool or uncapping fork so bees can take it easily.
Beekeepers must know the corrective actions for each disease and take the corrective actions.