Wax Moth: A Beekeeping Pest

Thursday 17 August 2023

There are two primary species of wax moth that can infest a western honey bee hive – the greater wax moth (Galleria mellonella) and the lesser wax moth (Achroia grisella). Although as beekeepers we classify wax moths as a pest species, in nature wax moths can be highly beneficial since they clean out old hives after a colony dies or absconds. In this week’s blog we will discuss what happens when wax moths infest a honey bee colony, how you can detect it, how it spreads, and how you both treat and prevent it in your bee yard.

Wax Moth: A Beekeeping Pest

Greater and lesser wax moth species can cause significant damage to colonies by feeding on beeswax, pollen, and remains of honey bee larvae. Detecting this pest species is done by inspecting the hive and finding wax moth larvae in the comb. Wax moth larvae typically tunnel within the comb while leaving webbing throughout the hive, which is another easily detectable sign of the pest. The greater wax moth larvae are creamy white but turn grey after reaching their fully grown size of 28 mm in length. The lesser wax moth larvae are smaller, 20 mm in length, and are white with a brown head (Department of Energy, Environment and Climate Action, 2023).

In their larval stage, these insects look like a more serious hive pest known as the small hive beetle. Therefore, it is important that beekeepers know how to correctly identify wax moth larvae. The distinguishing feature of wax moths is three sets of thoracic legs on the back of their body, and they have sets of uniform legs across their body. In contrast, small hive beetles only have thoracic legs without additional legs (Department of Energy, Environment and Climate Action, 2023).

Wax moth damage (VitaBeeHealth©2020)

In most cases, wax moths are spread through unmonitored frames of comb being stored. The moths prefer infesting stored combs that are not actively populated by bees. When beekeepers transport these frames between colonies, they can accidentally spread larvae to other hives. Additionally, unmonitored colonies of bees can quickly lead to infestation.

Preventing wax moths can be done by maintaining strong colonies of bees. Healthy colonies with large populations can naturally remove wax moth larvae themselves. By keeping the hive robust, beekeepers can potentially avoid infestation.

All life-cycle stages of wax moth can be killed by freezing at -6.7°C for 4.5hours, -12.2°C for 3 hours or -15°C for 2 hours. Therefore, freezing frames can be a very effective method for managing wax moths. After freezing, frames should be stored in a moth proof environment to prevent re-infestation. Sealed garbage bags provide a good insect-proof storage environment. Additionally, the use of cool rooms to store combs and protect them from wax moths has become increasingly popular (Department of Energy, Environment and Climate Action, 2023).

Some beekeepers place “moth traps” around their hives to lessen the number of adults entering the hive. There are various bait recipes available for beekeepers to try, but do not expect traps to be the complete answer to this pest problem. They will not make up for good hive management.

While wax moths do cause beekeepers some level of stress, their numbers can be controlled. The best way to treat wax moths is to use good beekeeping practices.

Connecting with ATTTA Specialists

If you’d like to connect with ATTTA specialists or learn more about our program, you can:

visit our website at https://www.perennia.ca/portfolio-items/honey-bees/

Email abyers@perennia.ca

Department of Energy, Environment and Climate Action (2023) Wax moth a beekeeping pest, Agriculture Victoria. Available at: https://agriculture.vic.gov.au/biosecurity/pest-insects-and-mites/priority-pest-insects-and-mites/wax-moth-a-beekeeping-pest#h2-0