List of diseases of the honey bee
Diseases of the honey bee or abnormal hive conditions include: == Pests and parasites == === Varroa mites === Varroa destructor and V. jacobsoni are parasitic mites that feed on the fat bodies of adult, pupal and larval bees. When the hive is very heavily infested, Varroa mites can be seen with the naked eye as a small red or brown spot on the bee's thorax.
Source: Wikipedia — List of diseases of the honey bee (CC BY-SA 4.0)