Technical Papers

NJ Homeowner's Guide to Webbing Clothes Moths

Wednesday, November 30th, 2016 by Bill Cowley

webbing clothes moth

Webbing clothes moths are found across most of the world, including New Jersey and Pennsylvania. Often referred to as fabric pests, they are the most common clothes moth in the United States. These moths have a tendency to hide when disturbed and are often found after damage to clothing or other fabrics are uncovered. 

Physical Characteristics: 

When at rest, the adult webbing clothes moth is only a quarter of an inch long. However, the moth has a wingspan of close to a half of an inch. Their wings are a pale golden color without any noticeable markings. Although the wings do not have distinctive markings, they are fringed with a row of golden hairs. Their heads are also a pale golden color and have a fluffy fringe of copper-colored hairs. The antennae are darker than the rest of the body, and the eyes are black. The adult is sometimes confused with the case making clothes moth, but those moths are slightly smaller and have three dark colored spots on each wing.

Mature webbing clothes moth larvae are approximately one half of an inch long. Their body is white or cream in color while their head capsule is a light to medium brown. 

Lifecycle: 

Webbing clothes moths usually begin to mate one to two days after they emerge from the pupae stage. These moths are polygamous. A male will mate with one female and then move on to another female. The female will begin depositing her eggs quickly and will lay approximately fifty eggs over a period of two to three weeks. They are laid in small groups or singly. When the female has completed laying all of her eggs she will die. Male webbing clothes moths outlive females. They continue to mate during the remainder of their life which can be more than a month. 

The webbing clothes moth lays her eggs among the threads or in the cracks of a suitable food material. This food material is most often wool but it can be hair as well. The female attaches her eggs to threads of fabric with an adhesive secretion she produces. The average egg will hatch in four to ten days as long as the temperature is warm. Once the eggs hatch, the larvae will molt many times. The webbing clothes moth’s larval period usually lasts from thirty-five days to two and a half years. 

When the larvae are ready to pupate, they will leave the area where they have been feeding in order to find a crevice or other protected site. Pupation usually lasts from eight to ten days in summer, or three to four weeks in winter. When webbing clothes moths are in a heated building they are able to continue development during winter months which allows the moths to go through a whole life cycle in four to six months. This means that under the right conditions, it is possible for the moth to have two generations in a year

Diet:

Adult webbing clothes moths have nonfunctional mouthparts and do not eat. The larval stage is the damaging stage of the clothes moth. The larvae prefer woolen articles, but will feed on hair, fur, feathers or similar animal products. The items that are most often damaged are wool clothing, wool carpets, wool rugs, upholstered furniture, furs, stored wool, animal bristles in brushes, and wool felts in pianos. Synthetic fabrics and cotton fabrics can be damaged when they are blended with wool. It is believed that in those cases the larvae may use cotton fibers to make their pupal cases. 

Although webbing clothes moths are usually found on wool fabrics, they can find food in almost any room of the house including bathrooms and kitchens. When larvae infest natural bristle hairbrushes or fur coats they clip off the individual hairs close to the surface. Larvae can also infest pet hairs that are found throughout the house. These hairs are often trapped under baseboards or in the air return vents of heating systems. When they are in the heating system they can easily be spread throughout the house. In some, more rare circumstances, larvae have been found in vacant wasp nests where they feed on insects that have died in wall voids or attics.

Signs of Infestation:

The damage done by webbing clothes moths can be extensive. Damage typically happens in difficult to see locations like clothes moth extreme damageunder collars or cuffs of clothing, in areas of carpeting covered by furniture, and in crevices of upholstered furniture. In many cases the woolen material that is damaged by the clothes moth will have furrows on the surface. These marks are caused by the larvae’s habit of “grazing” for food. Occasionally there will be long, irregular holes in the cloth; that is often a sign of a major infestation. 

Prevention:

Prevention is easier than removing an established infestation of webbing clothes moths. In most situations, woolen blankets and clothes that are used and cleaned often rarely have damage. Washing removes the moths. Wool carpets should be vacuumed often and inspected closely for evidence of pests. Shelves, dresser drawers, and storage boxes should be vacuumed before any wool products are placed in them. Any closets where woolen materials are stored should be vacuumed frequently with special attention being paid to the area beneath baseboards. 

All wool clothes and bedding should be laundered or dry cleaned prior to storage. Once they are cleaned, the best place to store wool items is in pest-proof containers with secure seals. It is important to not rely on cedar oil, chips, or cedar-lined closets as an effective means of controlling or preventing wool damaging pests. Young larvae that are exposed to high concentrations of cedar oil vapor die, but older larvae and adult moths are not affected. Another problem with cedar is it eventually loses its essential oils, making it ineffective with even young larvae.

It is important to make sure that the wool is clean because research shows that although webbing clothes moth larvae will feed on clean wool for a short time, they prefer soiled fabrics. The reason they prefer soiled fabrics is vitamin B is essential for larvae development. The larvae find vitamin B in the perspiration, urine, fruit juices, and milk that may soil clothes. If the larvae feed only on clean woolen goods, it is believed that they cannot survive more than two weeks.