The changing natural world at our doorsteps | Illustration and text by Patterson Clark
January 15, 2013
The clothes moth: Asleep in wool clothing
People inspired to dig through their drawers in search of a nearly forgotten wool sweater may sadly discover that something has beaten them to it, leaving a mark in the form of small holes in the fabric.
It's not the secretive clothes moth that does the damage, but the moth's larvae, which munch on wool (and fur and silk and feathers and dust bunnies) for one to 30 months before undergoing metamorphosis.
Adults emerge with a hunger only for mating. In search of a female, males launch weak, pathetic flights behind furniture and through dark closets. Unlike many moths, they're not attracted to artificial light. Sunlight sends them scurrying for cover.
Fertilized females snuggle down into
cushions, cuffs and collars to glue
down their small eggs, preferring
spots that have been soiled with sweat,
body fluids, food or beverages.
That's why it's best to have woolens cleaned before retiring them for the warmer seasons. Storing them in a sealed container will prevent moths from trespassing. Shaking out clothes, setting up moth traps and thorough household vacuuming will also keep them at bay.
Cedar closets won't kill moths, but extra-hot attics and clothes dryers on a high setting will.
So will mothballs made of naphthalene and para-dichlorobenzene. But moth haters are wise to think twice before deploying mothballs. Naphthalene is highly flammable, and both chemicals are toxic and can cause cancer in animals.
Buildings insulated with untreated wool batting can develop serious moth infestations. But there's a nifty biological solution that may help. Released
by the thousands, tiny parasitic Trichogramma wasps, each less than a millimeter long, home in on moth eggs, into which they plant their own eggs. Wasp larvae consume the moth eggs before a moth larva develops.
Even though they don't sting and are practically
invisible, an army of micro-wasps might be overkill for a home with a small population of clothes moths. Besides, damaged fabric can originate from a distressing array of perpetrators: Silverfish, carpet beetles and even crickets can gnaw a hole in a neglected sweater.
Sources: Nature Chemical Biology, Cornell University Department of Entomology, University of California Integrated Pest Management Program, Agralan, Journal of Entomological and Acarological Research
Tineola bisselliella was probably a denizen of African insect or bird nests before its accidental introduction to Europe by the early 1800s. It continues to spread as a fabric pest.