Wax Moth Treatment

The greatest threats when storing drawn comb for longer periods of time are mice and rats, mould, and wax moth. In this article I will guide you through how to perform effective wax moth treatment before putting boxes of drawn comb in storage for winter.

Wax moth

There are two species of wax moth, the Greater wax moth (Galleria mellonella) and the Lesser wax moth (Achroia grisella). Both species eat beeswax, with a preference for wax that has contained brood. They are pests that will affect colonies of honeybees and stored comb. In live colonies, they are most likely found in weakened or diseased hives. To beekeepers, they are more of a problem for the damage they can cause to unattended combs in storage. Especially when stored in areas that are dark, warm and poorly ventilated.

Wax moth damage on a brood frame from a dead hive.

Wax moth lifecycle

The wax moth undergoes the same metamorphosis as the honeybee, from egg to larvae to pupae to adult. The difference is that the length of the different stages varies greatly depending on the ambient conditions, especially temperature. At optimum temperatures of 29-33 degrees Celsius, it can develop very quickly. However, at lower temperatures, the whole process can take over six months. (3-30 days for egg to hatch, 28 days to six months at larval stage, and 1-9 weeks at pupal stage.) The adult moths live for up to 12 days (female) and 21 days (male). The male attracts the female using pheromones and ultrasound signals. The female will lay hundreds of eggs in batches immediately after mating.

Wax moth Damage to Comb

While at the larval stage, wax moth larvae will eat through comb. It also spins tunnels in the wax and finally spin a cocoon for the pupal phase. The adult moths do not eat. Hence, the damage is done as the larvae chew their way through the comb and spin their silken threads. Combs heavily infested with wax moth are not worth saving, hardly even worth melting down. However, if you have chickens, they do love a good feed of wax moth larvae. Otherwise, just cut out the wax and burn it. Salvage the frames. Frames with foundation are not very attractive to wax moths, so can be left in open boxes or exposed. Be aware that the wax will dry out and lose its shine, so it is better to store it enclosed.

How to Kill Wax moth

Acetic acid (80%) will kill the eggs and adults of wax moth. The larvae are more resilient. Especially when in the pupal stage so acetic acid treatment is best done before any eggs hatch. The vapours from the acid are what kill the wax moths and are not absorbed into the wax. Freezing frames will kill all stages of the moth. Hence, if you do not have a lot of frames to store, you could freeze them for a day or two before stacking them.

Acetic Acid Treatment of Combs

If using acetic acid, please note that it is highly corrosive. Read the labels carefully and follow instructions for use of gloves, goggles, and mask to protect yourself. Also cover the ground where you are working as it affects concrete and metal.

Acetic acid can be purchased from bee supply shops (usually for collection only) and chemical suppliers (supplied in minimum of 25 litre drums and provides shipping).

Step by Step Method for Treating Wax Moth

1. Put down a solid bottom board and stack 4-5 supers or 2-3 brood boxes with drawn comb.
2. Take a non-corrosive container and place an absorbent pad in it. Pour in approximately 250 ml of 80% Acetic Acid and allow the pad to absorb liquid. (Take what you have, but unused maternity pads or incontinence pads are excellent and can be reused, or some other absorbent material such as cotton or bamboo).
3. Remove the pad and place it over the frames of the top box.
4. Place a crown board or similar on top, with the holes closed.
5. Stack another lot of boxes on top and repeat.
6. Make sure there are no gaps between the boxes for the fumes to escape. Tape if necessary. Alternatively, to contain the fumes, place a very large plastic bag over the stack and secure at the bottom.
7. Leave for a week or two and then remove the pads. Store the pads in an airtight non-corrosive container for reuse next year. Acetic acid is highly corrosive, so if the pads are left in for longer, the metal in the frames and boxes will start to corrode, weakening the frames and discolouring the wax.
8. Air well and then stack the boxes on a solid bottom board and with a sheet or two of newspaper between each box. (Just in case of any wax moth surviving the treatment.) Put a crown board on top and cover the hole/-s or place a roof on top and store as cool as possible.

Hanna Bäckmo

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