Unit 3: Diseases and Enemies
1. Bee Diseases and Enemies
A healthy colony can be severely weakened or killed by a variety of diseases and pests. Recognizing them is a key beekeeping skill.
Bee Diseases
These are often microscopic pathogens that affect the brood (larvae) or adult bees.
| Type |
Disease Name |
Causative Agent |
Symptoms |
| Bacterial |
American Foulbrood (AFB) |
Paenibacillus larvae |
The most serious brood disease. Larvae die, decay into a brown, ropy ooze with a foul smell. Cappings become sunken and dark. |
| Bacterial |
European Foulbrood (EFB) |
Melissococcus plutonius |
Larvae die before capping, twisting into unnatural C-shapes, turning yellow then brown. Sour smell. |
| Fungal |
Chalkbrood |
Ascosphaera apis |
Larvae die and turn into hard, white or black "mummies" that rattle in the cell. |
| Viral |
Sacbrood Virus (TSBV) |
Virus |
Larvae die in their "sac" of skin, turning into a watery, granular fluid. |
| Protozoan |
Nosema |
Nosema apis / Nosema ceranae |
Adult bee disease. Infects the gut, causing dysentery (diarrhea), weakness, and inability to fly. |
Enemies (Pests and Predators)
These are larger organisms that attack the bees or the hive.
- Mites:
- Varroa destructor: The number one enemy of honey bees worldwide. This external parasitic mite sucks hemolymph (bee "blood") from both adults and developing brood, weakening bees and transmitting viruses.
- Tracheal Mites: Microscopic mites that live and reproduce in the breathing tubes (trachea) of adult bees.
- Wax Moths: The larvae of the Greater and Lesser Wax Moths are a major pest. They do not attack bees, but they tunnel through combs, eating wax, pollen, and debris, leaving behind a mass of silk webbing and feces that destroys the frames.
- Wasps and Hornets: These are predators that attack and kill foraging bees or even invade the hive to steal honey and brood.
- Ants: Can invade weak hives to steal honey and eggs.
- Other Predators: Birds (like bee-eaters), spiders, toads, and mammals (like bears) can also be a threat.
2. Control and Preventive measures
Good apiary management is focused on prevention, as treatment can be difficult and expensive. The golden rule is: "Keep colonies strong." Strong, populous colonies can defend themselves from most problems.
Preventive Measures (Prophylaxis)
- Apiary Hygiene: Keep the apiary clean and free of old, rotting equipment, and spilled wax/honey which attract pests.
- Strong Colonies: Unite weak colonies to make them strong. A strong population can defend the hive.
- Good Location: Ensure the site is dry, well-ventilated, and not in a "pest hotspot."
- Regular Inspections: Check colonies every 7-10 days for signs of disease or pests. Early detection is crucial.
- Reduce Entrance: For weak colonies, reduce the size of the hive entrance so it's easier for guard bees to defend.
- Disease-Resistant Stock: Obtain bees (queens) from reputable breeders known for hygienic behavior and disease resistance.
Control Measures (Treatment)
- For Wax Moths: Manually remove larvae and webbing. Store unused combs in a freezer or with paradichlorobenzene (PDB) crystals (air out before use).
- For Mites (Varroa): This is an ongoing battle.
- Chemical: Use approved miticides (e.g., formic acid, oxalic acid vapor, Apistan strips). Must be used carefully to avoid contaminating honey.
- Non-Chemical: Use "drone brood trapping" (Varroa prefer drone brood, so you can insert a drone frame, let them infest it, and then remove and freeze it).
- For Wasps: Set up wasp traps near the apiary.
- For Diseases:
- American Foulbrood (AFB): No cure. The entire colony, including bees and equipment, must be burned to prevent spores from spreading. This is often legally required.
- European Foulbrood (EFB): Can sometimes be treated with antibiotics (like oxytetracycline) or by requeening the colony.
- Chalkbrood/Nosema: Often clears up on its own if the colony is strong, well-fed, and dry. Requeening can help.
Common Mistake: Never use antibiotics "just in case" or for diseases like AFB. It does not kill the spores and can lead to contaminated honey and antibiotic resistance. Prevention is the only viable strategy.