Achroia grisella, the lesser wax moth is a moth of the Galleriinae subfamily of the Pyralidae family, of the Lepidoptera order. Wax moths were first seen in North America in 1806. People believe they came over with honeybees from Europe. The lesser wax moth is very common all over the world, except the colder regions. The larvae are the only ones that eat, the adults will not eat. Their larvae, wax worms, are a common food for pets such as lizards or fish. Wax moths live around 7 months. They go through four stages in their life cycle.
The lesser wax moth typically resides in milder climates and can be prevalent in areas such as Florida because of the year round warm climate. They take over the honeycombs of bee colonies usually when the bees are in a weakened state. Lesser wax moths can often be located in bee colonies where they lay their eggs, but in most cases the worker bees are there to eliminate them and keep them from over-running the colony. When the colony is going through turmoil, such as the loss of its queen bee, or starvation, the lesser wax moths completely take over. The larva though of the lesser wax moth can be very destructive to the honeycomb. It has been estimated that annually, beekeepers lose nearly 5 million dollars in damages due to these pests. There are many methods of control that beekeepers have adopted to ensure that these moths do not ruin the combs.
The bees themselves are the best form of control for these moths. They keep the populations at very low numbers and it is only when they are not strong enough that the moth populations will drastically increase. Beekeepers must make sure that the hives have active, populated colonies that are clean and free of debris. This will help to ensure the survival and strength of the bees who can then control the populations of the moths.
In the colder climates, storing the beeswax combs in freezing winter temperatures will stop there from being any chance of a moth infestation. Lesser wax moths need warm climates to thrive. There is also a fumigant known as paradichlorobenzene (PDB) that is used to destroy these moths. This can only be used on combs that are in storage. They are not successful on combs that currently are filled with honey.
Heating or freezing combs filled with honey also allow the honey to still be sold. The hotter or colder the temperature is, the less time that is required to make sure that the comb has been protected.
So far no traps have been found that completely protect honeycombs from the invasion of lesser wax moth larva.