Identifying Wax Moths
Much like Small Hive Beetles (SHB), the adult wax moth does not harm the hive. It is the larva that causes the real issues. The adult moth is about ¾ inch long with silvery/gray wings. The larva at the youngest stage is a very light white color. As they consume wax and pollen in the hive, they become a dark gray color. They also have a brownish-yellow head and can range from ¾ to 2 in. long. They can be extremely destructive to the comb in the hive. A severe infestation can turn a dead/dying hive or stored supers into a mass of webbing in a matter of days.
In the early stages you can see silk tunnels running through the comb. Freezing the comb quickly kills the larva and the frames can be easily cleaned by the bees and reused next year.
The final stage of a larva’s development is spinning an incredibly tough silken cocoon in the corners or crevices of a hive or burrowed into the wood in the hive. These can hatch into an adult moth anywhere from 28 days to 6 months depending on the season and feeding conditions. Scraping them out and freezing the equipment is the best way to kill them.
Do wax moths kill hives?
While they can certainly make a mess of comb, they do not kill hives. They are the cleanup crew that comes in after something else has damaged your hive. Wax moths are often blamed for the death of hives since they are the most visible sign of damage. But the vast majority of the time your hive was weakened to the point of near death by something else, often Varroa mites, and they were unable to keep the wax moth larva at bay. The best defense against them is keeping your hive strong and healthy.
Photo: NSW Dept. of Primary Ind. Schools
Defenses Against Wax Moths in Live Hives
The best defense is, 1) A strong hive, and 2) A hive that does not have too many boxes. There are no treatments for wax moths that are effective or safe in a living hive.
- A hive that only occupies a few frames within a hive is at risk of being overrun by wax moths. Focus on mites, proper feeding, new queens, etc. to make sure your hive stays healthy. Otherwise, the wax moths and SHB will begin eating the comb, pollen, and honey.
- Make sure bees are occupying at least 25% at a minimum of any box on the hive. If they are not, it’s time to remove a box. The exception here would be in late fall or winter. Once the temperatures are routinely freezing at night, wax moths are not a concern. If your top box on a hive is full of honey, but doesn’t have many bees in it, it does not harm them to leave it in case they need the honey later in the winter or early spring.
Cleaning frames infested with wax moths
If wax moths infest a frame of comb, you may or may not be able to reuse it. If there are only a few tunnels running through it, it can easily be reused. You can physically kill the larva and place the frames in a strong hive. They will easily clean and repair the frame.
Assuming you have a plastic foundation, if 50% or less of the frame is severely damaged you can scrape off the damaged portion and a strong hive will clean it and redraw the comb. Brushing a bit of melted wax on the bare foundation will help the bees draw it faster. If you use beeswax foundation rather than plastic, scrape it clean, and insert a new sheet of wax .
If the frame is over 50% webbing, it is usually best to scrape the foundation clean, recoat it with wax or pop the foundation out, throw it away, and place a new sheet of foundation in the frame.