Many disease symptoms may not be caused by a disease, but instead from unrelated factors such as queen failure, environmental damage, or pesticide poisoning. Alternatively, not all disease symptoms may be visible even if the disease is present. For definitive diagnosis of colony health problems consult with local state or provincial apiculture inspectors.
Match list of symptoms to diseases for diagnosis (diagnostic features appear in bold):
- Colony fails to build up in the spring or bees have swollen and discoloured midgut.
- Excessive defecation on colony entrance in the spring.
- A pile of dead or dying bees on the ground in front of the hive in the winter or spring.
- Nosema apis spores isolated from fecal material or bee midgut samples.
- Brood pattern spotty and patchy.
- Soft, sticky, and ropy dead brood that are light brown to black.
- Dead sealed brood. Cappings may be punctured several times.
- Tightly adhering brown to black scales lie uniformly on the lower side of brood cells.
- Colony failure.
- Microscopic examination of diseased brood or scales shows spores typical of Paenibacillus larvae bacteria.
- Brood pattern spotty and patchy.
- Watery and granular dead brood, not sticky and ropy.
- Most dead brood unsealed.
- Black rubbery scales that are twisted in the cell and that do not adhere tightly to cell wall.
- Microscopic examination of diseased brood or scales shows nonspore forming Melissococcus pluton bacteria.
- Bees have deformed and shrivelled wings.
- Brood dying and display symptoms not typical of brood diseases.
- Colony failure.
- Oval flat reddish brown mite attached to worker abdomen or thorax, within brood cells or collected on sticky paper placed below frames.
- Colony fails in spring or winter despite ample honey stores.
- Bees have disjointed wings and seem unable to fly.
- Microscopic dissection reveals prothoracic trachea packed with small mites.
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