Glossary
Larvae of the greater wax moth (Galleria mellonella) and lesser wax moth (Achroia grisella) that feed on beeswax comb, pollen, cocoon silk, and larval remains, tunneling through the comb and destroying it with silk webbing. Wax moths are primarily a storage pest; healthy, populous colonies usually defend against them successfully.
A critical distinction: wax moths rarely damage active colonies with healthy populations. Worker bees detect and remove wax moth eggs and small larvae through hygienic behavior. The problem arises in: weak colonies with insufficient population to patrol all comb, dead-outs (colonies that have died), and stored equipment (supers of drawn comb in storage). In these undefended combs, wax moth larvae can destroy an entire super of comb in 2 to 3 weeks.
Adult female moths enter hives or storage areas at night and lay eggs in cracks, comb crevices, and frame joints. Eggs hatch in 3 to 5 days at warm temperatures. The larvae immediately begin feeding on comb, burrowing through the wax and leaving silk-lined tunnels. As they grow, they consume increasingly large amounts of comb, pollen, and cocoon residue. After 5 to 7 weeks, larvae spin tough cocoons (often chewing depressions into wooden hive parts) and pupate for 1 to 5 weeks before emerging as adult moths to restart the cycle.
Prevention: Keep colonies strong (a populous colony is the best wax moth defense). Remove and freeze stored comb (48 hours at 0 degrees F kills all life stages). Store supers with adequate light and ventilation (moths prefer dark, warm, still conditions). Paramoth (paradichlorobenzene, PDB) crystals placed on stacked stored supers create fumigant vapor that kills moths (air out thoroughly before returning to bees). BT (Bacillus thuringiensis) spray on stored comb kills larvae that consume it. Cold storage below 45 degrees F prevents moth reproduction.
Signs include: white silk webbing across comb surfaces and between frames, tunnels bored through wax comb filled with dark, crumbly frass (larval feces), small oval depressions chewed into wooden frame parts (pupation sites), and adult moths (pale gray-brown, 3/4 inch long) flying near hive entrances at dusk. In stored equipment, the destruction is often discovered only when you open stored boxes and find ruined comb.
Lightly damaged comb (a few webbed areas) can be cleaned by scraping out the affected sections and freezing the entire frame for 48 hours. The bees will repair the cleaned areas. Heavily damaged comb (extensive tunneling, structural collapse) should be discarded. Render any remaining wax and replace with new foundation.
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