Wax moth damage, and which frames are worth saving

Track this against your own hives - free, on the web and the App Store.

Putting comb away so wax moth cannot get in is a separate job, and Cleaning, freezing and storing supers has the order. This page is the other half: telling the two species apart, reading the damage, and deciding what is worth keeping.

Wax moth is the second thing that went wrong

The National Bee Unit puts it plainly. Wax moth is a minor pest of honey bee colonies and a serious pest of stored comb. It will not kill honey bees and it will not harm a healthy colony. 1

What it does do is damage small or diseased colonies, and destroy unoccupied drawn comb in a colony that is weak, queenless, starving or diseased. Females get into the hive at night. They only manage it in daylight when the bees can no longer guard the entrance.

So wax moth in a live hive is telling you something, and it is not about the moth. Deal with the comb, then work out why that colony was too small to defend itself. The last proper look before winter is the list to go through.

Found in a box that is already dead, the moth is the aftermath rather than the cause. A dead colony: working out what happened is the post mortem to run before anything gets scraped or saved.

The two species

There are two in the UK. The greater wax moth, Galleria mellonella, is the more destructive and the more common. 1 The adult is about 15 mm long with a wingspan of 24 to 33 mm, reddish brown with ash white markings. A female lays a clump of 50 to 150 eggs in a crevice, and they hatch after five to eight days.

The lesser wax moth, Achroia grisella, is smaller: 10 to 13 mm long, an 11 to 14 mm wingspan, a yellow head. Each female lays 250 to 300 eggs. On egg numbers alone it sounds like the worse of the two. It is not. Its larvae are not found in comb the bees are living on, and they do not damage hive components.

Only the greater moth chews your woodwork, gnawing at wood to make somewhere to attach its cocoons. 4

What the damage looks like

A silk trail across the face of the comb is the usual first sign. 1 Under it a larva is tunnelling, often just below the cappings, feeding on honey, wax and pollen. The larvae are cream white with grey markings and reddish heads, from 1 mm up to 20 mm long.

There is a field test. Tap the edge of the frame with your hive tool, and a burrowing larva usually pokes its head out of a cell.

Bee pupae in tunnelled comb are rarely damaged, though some get caught in the silk and die there. That has a name, galleriasis. Left long enough, a whole box fills with white silk cocoons and dark specks of frass.

Bald brood, and what it is not

Larvae tunnelling under the cappings leave a line of open cells with pupae sitting exposed in them. That is bald brood. It is a disorder rather than a disease, and those pupae normally go on to emerge as fully formed adult bees. 5 It looks far worse than it is.

Read it properly, though. What it gets mistaken for is not minor.

• Bald brood. The opening is circular and slightly raised at the edge, not ragged and not nibbled. The pupae look plump and healthy, with no sign of cannibalism. Where wax moth caused it, the damage follows the larva, in straight lines across the frame.
• Not bald brood. Ragged or part opened cells, and pupae that look unhealthy or part eaten. Stop there. Registering on BeeBase, and what happens when foulbrood turns up near you covers what to do next.

It also happens with no moth in the hive, when frames sit too close together and the bees uncap brood to make room. There is no treatment. Put frames back where they came from.

Make sure it is not the small hive beetle

Small hive beetle larvae look enough like wax moth larvae to be taken for them, and one of the two is notifiable. A wax moth larva is soft bodied with a distinct darker head capsule. 1 A beetle larva is beige, 1 to 11 mm long, has three pairs of legs close to the head, and has spines along its back. 6 The beetle is not present in the UK.

Wax moth is not notifiable, and there is nothing to report. In England the notifiable diseases are American foul brood and European foul brood, and the notifiable pests are the small hive beetle and any species of Tropilaelaps mite. An owner or person in charge of a hive who knows or suspects that a notifiable pest is present in it must immediately notify the Secretary of State. 8 Varroa and foulbrood: what UK law asks of you has the difference between reporting and notifying.

What freezing does, and what it does not

Freezing kills every life stage, eggs included. The order it goes in is in Cleaning, freezing and storing supers.

The NBU gives two different times. The wax moth and fumigation fact sheets say 24 hours, or at least 24 hours. 2 The 2026 leaflet on pests of adult bees says 48. 4 Both say it kills every life stage, so if the freezer is free, the longer run costs you nothing. We use 48 as the working minimum, because it covers both figures. None of them gives a temperature. A domestic freezer is as precise as the wording gets, which is worth knowing if all you have is the ice box in a fridge door.

Three things freezing does not do:

• It does not keep the moth out. A frozen frame left in a warm shed is re-infested the first time a female finds it.
• It does not disinfect. The NBU says freezing may not be effective against Nosema. Acetic acid fumigation covers Nosema apis, though the fumigation fact sheet says it may not work on Nosema ceranae.
• It does not put wax back. Tunnelled comb stays tunnelled.

The one temperature the NBU gives for treating comb is the heat route: 49 °C for 40 minutes, with hot air moving right through the stack. Wax melts between 60 and 65 °C, so the heat has to be held steady. Frames of pollen or stores should not be heated at all.

Which frames are worth keeping

The question is not how bad the box looks. It is how much wax is left, and how dirty the comb was to start with. Larvae live on the impurities in wax, so they are found in brood comb, or in any comb holding old pupal casings or stored pollen. 1 Dark comb goes first.

• Keep it. Pale super comb with a silk trail or two and no real tunnelling. A lightly infested box can go back on a strong colony, and the bees will clean it out for you.
• Bin it. Comb tunnelled right through, comb solid with cocoons, and old dark brood comb, which should be going anyway.
• Judgement call. Frames of pollen. They are exactly what the larvae are after, so keep them only if they go straight into the freezer and stay sealed.

Drawn comb is worth keeping two to three years, or while it stays light in colour and in good general condition. Old dark brood comb should be melted down. 2 There is a separate rule for brood comb. Replace it at least every three years, and sooner after disease in the colony. Frequent use of varroacides containing thymol or tau-fluvalinate is the other trigger, because they can leave residues in the wax. 3

The pile that is going

Spent frames and old comb are most easily destroyed by burning. 3 To get the frames back instead, cut the wax out, keep the clean wax from super frames apart from the dirty wax out of old brood frames, and render it down by heating it gently in water. Hot wax is a fire hazard and it burns. Do not let it boil, do not leave it, and wear heat protecting gloves and eye protection.

Undamaged frames wash up in hot water at about 80 °C with soda crystals, 1 kg to 4.5 litres of water, and then take fresh foundation. Scrape the wax and propolis off the boxes first, because it gets in the way of the cleaning. 7

One rule catches people out. Do not put unclean frames or wax in the household waste. If it has not been boiled or burned, whatever is living in it goes out into the environment. Hive tools, and keeping them clean has the rest.

Storage that does not move the problem

Wax moth travels between sites on infested colonies and infested equipment. 4 Most of this job is not giving it a lift, and not leaving it a nursery.

• Keep each colony’s supers and combs to that colony, and mark the box and the top bars with the hive number. It is a disease measure first. It also stops you carrying eggs out of one box into a stack of clean comb. 7
• Never leave wet supers standing out. Put each one straight back on the hive it came off, and never on the ground.
• Seal a dead colony as soon as you find it, and get it off the site. It pulls in robbers as well as moths.

Prevention on the live hive is dull, and it works. Keep the colony strong, keep it clean, rotate the comb, and leave it no cracks, gaps or crevices to lay eggs in. 1

And the obvious one. A box you have just scraped out, put back in the shed beside the good comb, has moved the problem about three feet.