Diagnosing health in bees is harder than in humans — they can't tell us where they hurt. Here are the major diseases, parasites, insect pests, and animal threats every keeper should recognize.
Diseases
American Foulbrood (AFB)
Paenibacillus larvae
Signs: Scattered, sunken, discolored, perforated cappings; brown scale clinging to cell wall; foul odor; ropy 'string' test with toothpick.
Action: Destroy combs by burning; scorch interior hive walls; confirm with a professional apiary inspector.
Spores viable 40+ years in contaminated comb.
Parasites
Varroa destructor
External mite
Signs: Stunted/deformed bees, especially wings; compromised vitality; virus transmission.
Action: Monitor mite populations; use a drone comb as a trap — freeze overnight when capped, return to hive.
Mites quickly develop resistance to miticides.
Nosema
Protozoa (gut lining)
Signs: Hard to diagnose in the field; destroys adult bee gut lining; spreads viruses.
Action: Get professional help; most hobbyists leave it untreated.
Difficult for hobbyists to diagnose accurately.
Insect pests
Wax Moth
Galleria mellonella larvae
Signs: Silk-lined tunnels in comb; webbing and larval feces; destroyed comb.
Action: Maintain populous colonies; freeze stored combs (<10°F / -12.2°C for 24h); seal frozen combs in airtight bags.
PDB (paradichlorobenzene) is no longer recommended — contaminates wax.
Small Hive Beetle
Aethina tumida
Signs: Hive-product damage, especially pollen.
Action: Maintain populous colonies; freeze stored combs to kill all stages.
Control strategies change rapidly — seek current information.
Animal pests
Skunks
Scratch at hive entrances at night and eat emerging bees. Install a fence around the hives.
Mice
Damage lower combs in winter. Cover the entrance with #3-mesh galvanized hardware cloth.
Bears
Can destroy an entire apiary overnight. Install an electric fence before the apiary is discovered.
Ants
Invade hives and steal stores. Use hive platforms with legs treated with sticky barriers or repellents.