Wax moths (Galleria mellonella and Achroia grisella) are a pest of honey bees that causes significant damage to honey bee colonies by feeding on beeswax, pollen, and remains of honey bee larvae. The larvae of wax moths typically tunnel within the comb while leaving webbing and frass throughout the hive. Most often this pest is an issue with stored beekeeping equipment but can also be a problem with weaker active colonies. Last year all Canadian provinces were invited to participate in an emergency use registration for a larvicide, with the commercial name “Certan”, that we will be discussing in this week’s blog.
Treating Wax Moth with Larvicides
Wax moths (greater wax moth, Galleria
mellonella and lesser wax moth, Achroia
grisella) are long
existing pests of honey bees. The larvae of these pests cause serious damage by
destroying the comb, as they tunnel through the hive leaving webbing, frass,
and even galleries in the wood1. Most often wax moths cause issues
in stored beekeeping equipment. However, they can also cause damage in weaker
active colonies1.
Last year all provinces were invited to participate in an emergency
use registration for a larvicide, known as Certan. Certan is a biological
control for the prevention of wax moths on stored drawn frames. Certan uses Bacillus
thuringiensis (Bt), which is a bacterium that occurs naturally in soil2.
The active ingredient in this pesticide product (Bta ABTS 1857) controls wax
moth infestations by producing a crystallized protein that is toxic to wax moth
larvae2. This micro-organism is harmless to humans and honey bees,
leaves no residue in wax or honey, and does not alter the taste of honey2.
The product is intended to be used after the honey harvest
when the frames are stored, and it will kill young wax moth larvae. Therefore,
the product is intended to be used prior to wax moth infestations2.
A single application of the product will provide very high efficacy against wax
moth until the following season.
Last year only Manitoba and Nova Scotia asked to participate
in the emergency use registration of the product, which is only viable until
May 2024. Currently the product is still available to both provinces through
Dancing Bee Equipment Manitoba, but it is unknown if it will be available by
summer 2024. Whether or not the product is available this summer will depend on
if the provinces, and or Country, pursue a full registration with Health Canada’s
Pest Management Regulatory Agency.
Larvicides are not the only solution to controlling
these pests. Preventing wax moths can be done by maintaining strong colonies of
bees. Healthy colonies with large populations can naturally remove wax moth
larvae themselves1. By keeping the colony robust, beekeepers can
potentially avoid infestation.
Additionally, all life-cycle
stages of wax moth can be killed by freezing at -6.7C for 4.5hours, -12.2C for
3 hours or -15C for 2 hours1. Freezing frames can be an 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. Also, the use of cool rooms to store
combs and protect them from wax moths has become increasingly popular1.
While wax moths can be a serious issue
for beekeepers, good beekeeping practices is one beneficial tool to manage the
pests.
References
- 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
- Certan: Wax moth treatment: 5 oz. Dancing Bee Equipment Manitoba. Available at: https://dancingbeemanitoba.com/products/certan-wax-moth-treatment