Skip to main content
Version: 0.1.0

Diseases & pests

Healthy colonies fend off most problems on their own. Your job is to keep them strong, well-fed and well-ventilated, then watch for the early signs of trouble so you can act before a small problem becomes a lost colony, or spreads to your neighbours.

This page is a quick field reference to the diseases and pests you are most likely to meet. For each one you will find the typical signs and the general approach to management.

:::danger This is general information, not a diagnosis Several of the conditions below are notifiable in many countries, meaning you are legally required to report a suspected case to your national bee health authority. Diagnosis can be difficult and several conditions look alike. If you suspect a serious or notifiable disease, stop, do not move bees or equipment, and contact your local bee inspector or veterinary authority immediately. Follow their instructions; they take precedence over anything written here. :::

Recording what you see​

When something looks wrong, write it down. In Openbeehive you can log a finding on the relevant inspection, set a follow-up task, and record any treatment you apply. Good records help you, and your inspector, spot patterns over time. See Inspecting for how to run a thorough check.

Varroa (Varroa destructor)​

The single most important pest for most beekeepers worldwide. This mite feeds on developing and adult bees and spreads damaging viruses.

Signs: mites visible on bees or in drone brood; deformed wings; patchy or "spotty" brood; a colony that dwindles in autumn for no obvious reason. Monitor with sugar-roll, alcohol wash or a sticky board under a mesh floor.

Management: monitor mite levels through the season and treat based on counts, not the calendar. Combine approaches (an "integrated" strategy) such as drone-brood removal, brood breaks and approved miticides, choosing products suited to the season and whether honey supers are on.

See the full guide: Varroa.

American foulbrood (AFB)​

A serious bacterial brood disease caused by Paenibacillus larvae. Its spores survive for decades and spread easily on equipment, making it the most feared disease in the apiary.

Signs: sunken, greasy, perforated brood cappings; an uneven, "pepperpot" brood pattern; a foul smell; dead larvae that pull out into a brown, ropey thread (the "matchstick" or ropiness test); hard, dark scales stuck flat to the cell base.

Management: AFB is notifiable in most countries. There is no safe cure for the hobbyist; treatment is usually destruction of the colony and contaminated equipment by burning, under the supervision of your bee inspector. Do not attempt to treat it yourself or move suspect hives.

:::danger Notifiable If you suspect AFB, close the hive, keep it where it is, and report it to your bee health authority straight away. :::

European foulbrood (EFB)​

A bacterial brood disease caused by Melissococcus plutonius that affects unsealed larvae.

Signs: larvae that die before capping; twisted, discoloured (yellow to brown) larvae lying unnaturally in their cells; a sour smell; a patchy brood pattern. Unlike AFB, the remains are usually not ropey.

Management: EFB is notifiable in many countries. Strong, well-fed colonies often recover, and a comb-change ("shook swarm") may be advised. In some regions antibiotics are permitted only under official direction. Always follow your inspector's guidance rather than self-treating.

Chalkbrood​

A fungal disease (Ascosphaera apis) that kills larvae, which then dry into hard, chalky "mummies".

Signs: white, grey or black mummified larvae in cells, on the hive floor, or dragged out onto the landing board.

Management: usually a sign of stress, damp or a weak colony. Improve ventilation, keep colonies strong, requeen from hygienic stock if it persists, and replace badly affected combs. Not normally notifiable, and rarely fatal on its own.

Nosema​

A gut disease caused by microsporidian parasites (Nosema apis and Nosema ceranae) that shortens bees' lives.

Signs: often none that are obvious; possibly dysentery (brown streaking on the hive front, with N. apis), crawling bees, slow spring build-up and dwindling. Confirmation needs microscopy.

Management: reduce stress, ensure good stores and a dry, well-ventilated hive, replace old comb regularly, and requeen weak colonies. Good apiary hygiene is the main defence.

Wax moth​

Two moths (greater and lesser wax moth) whose larvae tunnel through comb, leaving silky webbing and frass.

Signs: webbing and tunnels through stored or neglected comb; ruined frames; debris on the hive floor.

Management: wax moth is an opportunist that attacks weak colonies and stored comb, not a healthy hive. Keep colonies strong, and store spare comb cool, dry, light and airy. Freezing frames kills all stages.

Small hive beetle (Aethina tumida)​

An invasive beetle whose larvae tunnel through comb and brood, fouling stores so they ferment and "slime out".

Signs: small dark beetles running across combs when you open the hive; larvae in comb; fermenting, slimy frames with a smell of rotting oranges.

Management: Small hive beetle is notifiable in many regions and absent from some. If you are in an area where it is not yet established and you see it, report it immediately. Where present, keep strong colonies, use in-hive traps, and avoid leaving comb or spilt honey exposed.

Tropilaelaps mites​

Another invasive brood-feeding mite, currently restricted to parts of Asia but a serious threat elsewhere.

Signs: small fast-moving mites on brood combs; deformed and dead brood; symptoms resembling severe varroa.

Management: notifiable in many countries where it is exotic. If you are outside its known range and suspect it, report at once.

Viruses​

Bees carry many viruses, including Deformed Wing Virus (DWV), Chronic and Acute Bee Paralysis, Sacbrood and Black Queen Cell Virus. Most are kept in check until something, usually varroa, lets them flourish.

Signs: deformed or shrivelled wings, shaking or trembling bees, hairless "greasy" black bees, crawling at the entrance, and unusual brood mortality.

Management: there is no direct treatment. The most effective control is keeping varroa low, since the mite spreads and amplifies these viruses. Strong, healthy, well-nourished colonies are far more resilient.

A note on robbing and drift​

Many diseases and pests spread between colonies through robbing, drifting bees, and shared equipment. Reduce the risk by:

  • avoiding spills of honey or syrup in the apiary;
  • not swapping combs or tools between hives during an outbreak;
  • cleaning hive tools between colonies;
  • spacing and orienting hives to limit drift.

:::tip Know your regional rules Disease status, which conditions are notifiable, and which treatments are legal all vary by country and sometimes by region. Register with your national bee health scheme if one exists, and get to know your local association and bee inspector before you need them. :::

See also​