Problems with wax moths in your beehive are often a symptom of weak or stressed bees. Preventing wax moths in beehives and wax moth treatment are important basic beekeeping skills.
There are two species of wax moth which are common. The Greater wax moth (Galleria mellonella) is the more common pest I have seen. The Lesser wax moth (Achroia grisella) can also be a pest but is less common generally.
Use queen excluders to keep your super comb free of bee silk. Wax moths need to eat something with protein in it in order to grow. Beeswax on its own is insufficient to nourish them.