Wax Moths can be a serious problem for beekeepers. They are often blamed for the death of a honey bee colony. However, this pest is often a symptom of a larger problem or beekeeper mistake in the hive. Learn how to identify a wax moth infestation and the various wax moth treatment options.
Wax Moths – Pests of the Beehive
Wax Moths (also called “bee moths) are a natural part of the environment. They are attracted to beehives by the scent. Beeswax, honey, pollen and other hive odors lure the moths inside.
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While a wax most infestation can destroy a colony, most hives will not fail. A colony with a strong population is well equipped to throw those pesky moths out!
However, weaker honey bee colonies are at the greatest risk of severe wax moth damage. For a very small hive already struggling to survive, an infestation of moths may be the last straw.
What Is A Wax Moth? – Identification
There are actually two types of these beehive pests to consider. The Lesser Wax Moth (Achroia grisella) – (left) and the Greater Wax Moth (Galleria mellonella) – (right) are both smaller grey-beige moths.
Both are attracted to the hive by odors. They are most active after dark and often enter the beehive at night. In the hive, most beekeepers won’t recognize which type of moth is present. In fact, you may not see one at all – but that doesn’t mean it has not been there.
A strong bee colony with plenty of worker bees is in little danger. Chasing adult moths from the hive and possibly removing moth eggs, bees keep the damage to a minimum.
Adult bees generally do not remove moth larvae. If there are not enough bees to patrol all the comb, the moths may get the upper hand.
Life Cycle of the Wax Moth
Females moths can lay up to 600 eggs in clusters on the honeycomb or in crevices of the hive. The spaces between boxes are also a favorite location.
Moth eggs can hatch in 3 days during warm conditions. These wax moth larvae (called wax worms by some beekeepers) are the true pests.
The larvae are very small white grubs. To the untrained eye, they don’t look much different than bee larvae. In fact, it is not uncommon for a new beekeeper to say – “hey, my baby bees are crawling out of the cells!”
The larval moth stage can be completed in 19 days from hatch in warm weather. When larvae feeding stage ends, larvae spin white cocoons for the transformation into adults.
They will often eat away wooden surfaces in the hive creating a wavy surface and causing damage to the wooden parts of the beehive. The cocoon stage lasts about 14 days before adult moths emerge and begin the life cycle again.
Diagram of Wax Moth Development
What do Wax Moth Larvae Eat?
Wax Moth larvae eat beeswax, the remains of bee larval cocoons, bee cocoon silk and bee feces in the cell. Older, darker comb that has been used to raise baby bees and hold pollen is very attractive to the adult moth.
This is the type of honeycomb that provides the most nutritious food for growing moth larvae. Moth eggs laid in this region will be nearest to their food source.
Contrary to the information of some sources, wax moth larvae can live on pure beeswax. This is another reason to try to keep honey bee brood out of your supers intended for collection. This can be accomplished by using a queen excluder.
Evidence of a Wax Moth Infestation
The easiest method of detecting wax moth problems is the presence of webbing and tunnels in the honeycomb. Moth larvae leave behind noticeable tunnels with a “spider-like” webbing.
Larval feces (small cylindrical black pieces) can also be seen on the bottom board and in the webbing on the comb.
In unguarded comb, they continue to eat until all the wax has been consumed. Leaving a webby, mess for the beekeeper to clean.
Sometimes, wax moth larvae can be found crawling on the comb surface. The larvae are easily confused with Small Hive Beetle larvae, another bee pest.
As wax moth larvae tunnel through the comb just below the cappings – they may cause a condition called “bald brood”. The moth larvae are partially removing the cell caps as they burrow.
Then worker bees chew the rest of the cap off. This exposes the head of developing bee pupae often resulting in deformed adult bees.
Wax Moth Treatment and Prevention
The best way to treat wax moths in your hives is to avoid letting the situation get out of control. There is no chemical that you can put in your hive to kill moth larvae and not damage the bees. Here are some techniques that can help your bees be able to defend themselves against wax moths.
- keep all colonies strong
- do put too many boxes on the hive
- monitor hive population all season
- consider trying some outside moth traps
1. Keep strong healthy colonies with lots of bees. Are there enough bees to cover most of the comb surface? Wax Moths can be a problem during any of the warm months of the year.
Be careful with new colonies or when making splits – you need enough bees to patrol the comb.
When you split a bee hive, failure to include enough bees in each part could lead to problems with moth damage. Any time you mix warm weather conditions with weak hives, there is a potential for a wax moth infestation.
Likewise, a colony that loses it’s queen may dwindle in population unless the beekeeper is able to requeen in time. Monthly inspections are a minimum during warm weather.
2. Don’t put too many boxes on the hive at one time if the population of the hive can not patrol the comb. We all make this mistake sometimes as we prepare for the honey flow.
A new hive started from buying bees in a package will need several months to build a population. It may be a target especially if the beekeeper adds too many boxes at once.
3. Monitor the population of your hives during the season. If a colony swarms and experiences a dramatic drop in bee population – they could be at risk.
4. It is near impossible to keep moths out of a hive. In my opinion, it is an exercise in futility to try. However, some beekeepers do set up various types of moth traps near the bee yard – maybe they help?
Recipe for Moth Trap Bait
Some beekeepers put out “moth traps” to try to lessen the number of adult moths entering beehives. These traps are commonly home-made with many different “bait” recipes in use.
This is a common one : take an empty soft drink bottle – with a one inch hole placed near the slope of the neck. Fill the bottle with 1 cup of water and sugar, ½ cup of vinegar – add a banana peel. Let this mixture ferment for a couple of days. Then, tie it to a tree near the bee yard.
Experiment with different bait recipes. But don’t expect traps to be the complete answer to moth problems. They will not make up for good hive management.
Protecting Stored Honey Supers
One of the biggest mistakes made by new beekeepers is improper storage of honey supers. Your bees did a great job and you want to save all that beautiful wax for them to refill next year.
Well, Wax moths are not only a danger to occupied hives. In fact, they do some serious damage to draw comb. Eggs can be present on those frames even if you don’t see any. Then you place them in a nice dark place – perfect for moth larva – they love the dark.
If you must put your supers away, be sure to prepare them first. Freezing comb for a few days and then place it in a tight storage container.
Or use approved chemical repellants designed for this use. Another option is the use of a Bacillus Thuringiensis (Bt) solution such as Certan.
Cleaning Up a Hive Infested with Wax Moths
If you have been in beekeeping for a while, you have likely experienced a box full of moth larvae and webbing. What a mess.
Don’t be too quick to throw away those frames of comb. Comb that has a moderate amount of damage can be reworked by a strong colony. You may find a few bees trying to hang on or the colony may already be dead.
If your bees are all gone (or too few to survive), it is best to disassemble the hive. Scrap away any comb debris webbing etc. You will need to scrape any cocoons away from the frames and inside of the box.
Beekeepers who use plastic foundation have less of a clean up job on wax moth infected frames. They can scrap the mess off that plastic and the bees can reuse the foundation.
Some debris may still be down in the wax imprints but that’s no worry. This is not a disease – it is a pest. You could pressure wash the foundation but there is usually no need.
Those of us who prefer beeswax foundation need to keep extras on hand so we can replace the wax foundation. Any “good” frames of comb that you remove from the hive should be frozen for 2 or 3 days to kill any moth eggs and then stored in a moth free place until needed.
Scorching the inside of the box with a propane torch will aid in killing any cocoons or eggs that are not easily visible. Sometime I do this and other times I don’t bother – a good scraping usually does the job well enough.
Strong Colonies Can Repair Wax Moth Damage
Seeing an adult moth or a few moth larvae is no cause for panic. Even a strong colony may have the occasional moth or wax worm. In the case of a minor problem, the bees will clean and repair the comb.
If the colony still have enough bees and a queen, they may still be saved. Remove the frames that are most infested or damaged and reduce the hive size down to fewer boxes.
A 2 deep hive may need to temporarily be reduced to a 1 story deep. A single deep may need to be in a 5 frame nuc for a while until the colony population rebounds.
While they may cause headaches for beekeepers, wax moths are not an enemy of honey bees. They are a natural part of the bee ecosystem. In the wild, bee moths enter an abandoned colony and clean up old comb. This leaves a clean disease-free cavity for the next bee swarm.
The best way to treat wax moths is use good bee management practices. The same can be said of Earwigs and roaches. Keeping colonies strong with the proper amount of space to guard will allow the bees to do the job.
It is a common occurrence for a beekeeping student from my online beekeeping class to tell me “My hive was killed by wax moths”.
However, wax moths don’t normally cause bee colonies to fail. Finding an infestation in your hive is just a symptom of another issue the colony has.
You will never keep them all out of the hive. Instead, help your bees be strong enough to control the problem on their own and provide support with traps, box manipulation etc.
Wax moth larvae go through a pupal stage and turn in to adult moths.
No, wax worms have small jaws and mouth parts that pose no danger to human skin.