How do I get rid of wax moths in a beehive?

Freeze infested frames at 20°F for 24 to 48 hours to kill every life stage, then store comb bee-tight in light and airflow. Strong colonies remove wax moth larvae themselves; moths only take over comb that bees are not guarding.

Do wax moths kill bee colonies?

Almost never. Wax moths move into comb after a colony has already collapsed or dwindled, usually from varroa mites, queenlessness or starvation.

What is B402 or Certan for wax moths?

A Bacillus thuringiensis aizawai spray, harmless to bees and people, mixed 1 part to 19 parts water and sprayed on both sides of clean frames. It kills newly hatched larvae, so it is a preventive for stored comb, not a cure for an active infestation.

Wax Moths in Beehives: Signs, Life Cycle & Treatment

Wax Moths in Beehives: Identification, Life Cycle, and How to Protect Your Comb

You pull a super out of the shed, or open a hive that has gone quiet, and the comb is a mess of silk webbing, tunnels, dark frass and fat gray larvae. Wax moths. The first question every beekeeper asks is "how do I kill them." The better question is "why were they able to move in," because wax moths are a symptom, not a cause.

The short version

Wax moths cannot take over a strong colony. They move into comb that bees aren't guarding: stored supers, and hives already collapsing from varroa mites, queenlessness or starvation. Freeze frames at 20°F for 24–48 hours to kill every stage, store comb in light and airflow, and keep your colonies strong with a mite wash and an oxalic acid vaporizer on standby.

Greater vs. Lesser Wax Moth: Identification

	Greater wax moth (Galleria mellonella)	Lesser wax moth (Achroia grisella)
Adult	12–20 mm long, mottled gray-brown, wingspan about 40 mm	About 12 mm, silver-gray to beige with a yellow head
Larva	Up to 28 mm, cream to gray, very active	Up to 20 mm, smaller and slimmer
Eggs	Up to 1,800 per female; 300–600 is typical; hatch in 3–5 days at 84–95°F	Hatch in 5–8 days
Signature damage	Heavy silk webbing, tunnels through comb, cocoons chewed into wood, "bald brood" in straight lines	Lighter webbing, also causes bald brood

The larvae don't eat wax for the wax. They want the protein in old brood comb: cocoons, cast skins, pollen. That is why dark, used brood frames get destroyed first and new white comb is usually ignored.

Why Wax Moths Only Win in Weak Hives

A healthy colony with a high bee-to-comb ratio polices every inch of comb and hauls larvae out before they can spin a tunnel. Wax moths get a foothold in two situations: comb with no bees on it at all, and colonies that have dwindled below the point of being able to guard what they have.

Extension services list the reasons colonies dwindle in the same order every time: starvation, queen failure, pesticide exposure, disease, and above all varroa mites. In our experience the hive that "got wax moths" in September was almost always a hive whose mite load crossed the line in July. The bees were dying of deformed wing virus weeks before the first moth found the gap. If you find a webbed-out hive, don't just clean it. Read what's left in the box, and wash your other colonies for mites this week.

Protecting Stored Comb

Freeze it. 20°F (about -7°C) for 24–48 hours kills eggs, larvae, pupae and adults. A chest freezer is the best wax moth investment a beekeeper can make. Then store the frames bee-tight and moth-tight, because a thawed frame can be re-laid on within days.
Light and air. Wax moths avoid bright, ventilated spaces. Stack supers crosswise with gaps, or hang frames in a lit room. Sealed, dark stacks in a warm shed are exactly what the moth wants.
B402 (Certan). A Bacillus thuringiensis aizawai spray, harmless to bees and people, mixed 1 part to 19 parts water and sprayed on both sides of each frame. It only kills newly hatched larvae, so it is a preventive for clean comb, not a cure for an infested one. One application typically protects comb through to the next season.
Cold storage. Comb kept near 39°F or below stays effectively moth-proof.
Skip the mothballs. Naphthalene mothballs are toxic and can contaminate wax. Paradichlorobenzene ("Para-Moth") is the only crystal traditionally used, never on comb holding honey for people, and its use is increasingly discouraged. Freezing and Bt are the modern answer.

Protecting Live Colonies

Don't give a colony more comb than it can cover; a nuc in a double deep is an invitation. Combine or requeen weak colonies before fall. And keep mites down, because a colony with a mite wash under 2 per 100 bees will never let a wax moth larva survive. That is the whole reason we treat with oxalic acid vaporization on a schedule instead of reacting: the dosage and schedule guide covers how.

Wax Moth Myths

"Wax moths killed my hive." Almost never. They ate the comb after the colony collapsed from something else, usually mites.
"I froze it once, so it's safe." Freezing kills what is there. Re-exposure re-infests.
"Household mothballs are fine." Naphthalene is not, and it ends up in your wax.
"Bt will clean up an active infestation." It kills only young larvae. Freeze first, then spray.

Tools We Use (and Recommend)

InstantVap Oxalic Acid Vaporizer: the cordless, battery-powered oxalic acid vaporizer we use in our own yards to keep mite loads low, which is the single best defense against every problem on this page. See the Lite, Compact, Original and Turbo. Lorob Bees is the primary US seller, with stateside customer service and a warranty we stand behind.
Mite Monitoring: the Easy-Check mite wash. How to do a wash in five minutes.
Oxalic Acid: EPA-registered EZ-OX.

Happy Beekeeping from the Lorob Bees Team

Written by Rob Pollock

Rob keeps bees in Baltimore, Maryland, and owns Lorob Bees. He built and repaired his own corded oxalic acid vaporizers for years before becoming the primary US seller of the InstantVap, and he still picks up the phone when one needs service. Oxalic acid vaporization is the thing he cares most about in beekeeping, because it's the treatment that keeps hives alive without breeding resistant mites. More about Lorob Bees.

Keep reading: Explore all Lorob Bees beekeeping guides — varroa, oxalic acid vaporization, pests and diseases, all in one place.

Sources

NC State Extension, Wax Moth Control in Stored Equipment, 2026
LSU AgCenter, Galleria mellonella, Greater Wax Moth, 2024
UF/IFAS, Lesser Wax Moth, Achroia grisella (EENY-637), rev. 2026
UF/IFAS Extension Polk County, Florida Farm Pest: Wax Moths, 2025
Vita Bee Health, B402 (Certan) wax moth control

General beekeeping information, not a substitute for the product label. Always read and follow the label of any product you use in a hive.