Moths that are economically significant fall into one of two categories; fabric moths or grain moths. Among the most commonly found moths in New England are the Indian meal moth, the Mediterranean meal moth, the webbing clothes moth and the casemaking clothes moth.
A clothes moth infestation often has a very innocuous beginning; a female moth flies in from out of doors and lays up to 200 eggs at a time in a place where the chances of survival are the greatest. A moths life cycle exhibits complete metamorphosis. The egg hatches and the larva begins to feed and grow immediately. When it is time to pupate the larva spins a cocoon and emerges as an adult. It is the larvae (caterpillars) that cause damage; adults do not feed. The life cycle may be completed within one month under the most favorable conditions; about 75 degrees Fahrenheit with 75% relative humidity. Generally it takes longer than this and can take as long as several years.
Unlike other animals, clothes moths can digest and utilize keratin, an important energy source and the chief protein in hair, feathers, and skin (including dead skin cells that humans and pets shed) as well as fingernails, horn and claws. So, in addition to animal based fabrics they are able to readily find other food sources.
Discussion of the Indian meal moth and the Mediterranean meal moth can be found on the grain insect page.
In our experience, instances of webbing clothes moths outnumber case-making clothes moths by at least 10 to 1. We have received more calls for webbing clothes moths in the last 5 years than we did in the 25 preceding years, demonstrating that they are becoming more of a problem. The most likely locations for these moths to be found are in the wool sweater drawer, the closet, woolen carpets and wall hangings. Although they are capable of infesting other products, their preference is for fabrics made from animal fiber such as wool or silk. Another factor is that they prefer soiled fabrics to clean fabric.
Unlike other moths that can be seen flying around lights at night, webbing and case-making clothes moths prefer dark closets, attics and other areas where they hide in dark corners or folds of fabric. Unfortunately, once you begin seeing them flying around the infestation is generally well advanced.
Moths do not pose a health threat, excepting the emotional trauma caused by the ruin of your favorite cashmere sweater or Persian carpet.
Case-making and webbing clothes moths destroy fabrics. They make holes in everything from expensive dresses, sweaters, suits and coats to upholstery, rugs and blankets to furs and leather goods causing substantial economic damage.