Bee Diseases and Pests

Most colony losses are caused by diseases and pests, above all by varroa and the viruses it carries. This section summarises what to look for at the hive, which sign points to which group of problems, and which checks you should carry out throughout the year. Details are on each disease's own page.

How to approach problems

Disease management does not mean reaching for a medicine once symptoms appear; it means catching problems early through regular observation, measurement and record-keeping. The sequence that works is:

1. Observe: Regularly inspect the hive entrance, the brood nest and the adult bees.
2. Measure: For countable agents such as varroa, rely on counts rather than guesswork.
3. Compare: Compare the sign with similar conditions; never make a firm diagnosis from a single symptom.
4. Decide: Management and biotechnical measures first, then an authorised product if needed.
5. Verify: Measure again after treatment and record the result.

The aim is not to eliminate the pest completely but to keep it below the damage threshold. Unnecessary and incorrect use of medicines leaves residues in honey and speeds up the development of resistance.

Main groups

Warning signs to watch for at the hive

• If the brood pattern is irregular (gaps between cells with eggs, a patchy appearance): consider brood disease, varroa and a weak or ageing queen together.
• If cappings are sunken, perforated or greasy-looking: always rule out American foulbrood; carry out the matchstick test.
• If open larvae look yellowed, twisted or melted: think of European foulbrood.
• If there are young bees with crumpled wings that cannot fly: the varroa load is high; do a mite count immediately.
• If there are many dead or crawling bees in front of the hive: you need to distinguish between poisoning, starvation, viruses and nosema.
• If you see silk webbing and tunnels in the comb: wax moth; usually a sign of a weak colony.

Notifiable diseases and pests

Some agents are a problem not for a single apiary but for the whole region. American foulbrood, European foulbrood, the small hive beetle (Aethina tumida) and Tropilaelaps mites are notifiable. If you suspect any of them:

• Do not attempt treatment yourself and do not use antibiotics.
• Leave the hive where it is; do not move frames, honey, bees or equipment, and do not sell colonies.
• Report it to the official veterinary service / local agriculture authority; an official veterinarian decides on the diagnosis and the action to be taken.

Seasonal inspection calendar

The most effective prevention

• Regular measurement and record-keeping: Write down what was done to which hive and when; problems show up early in the records.
• Comb renewal: Old, dark combs accumulate pathogens and residues; replace part of them every year.
• Tool and glove hygiene: Clean them between hives, especially after a suspect colony.
• Reliable sources: Do not buy colonies, queens, combs or honey from unknown sources; never feed bees honey of unknown origin.
• Strong, well-fed colonies: Weak colonies are vulnerable to disease, robbing and pests.
• Preventing robbing: Do not leave honey and combs exposed, and reduce the entrances of weak colonies.