Have you ever noticed mysterious little holes that appear in your clothes and you can’t remember ever snagging or running into something that would have caused them? You could be looking at an example of insect damage! Little tiny pesky insects, so small you hardly see them, may be doing considerable damage to textiles around your home. Generally, you won’t notice them, or the damage they’ve done, until it’s too late. And it’s the babies (larvae) that do the damage…to everything from sweaters, pants, and jackets, to wool rugs, and decorative needlework on your walls. The only damage the parents do is leaving behind their eggs, which hatch the larvae, which then feast on your fine items! Moths and carpet beetles were the originators of the “high protein” diet, as that’s what they thrive on…the protein found in fabrics containing natural fibers.

Depending on the time of year, insect damage ranges from the 2nd to the 5th most common consumer problem related to clothing. Insect damage to textiles in the United States is estimated at $200 million annually. According to the National Pest Control Association, fabric pests are making a comeback because most of the residual insecticides formerly used in their control (dieldrin and DDT) have been banned. This has caused those who deal with the insect damage to take a multi-faceted approach to spotting early signs of infestation, recognizing its causes, controlling the environment, understanding the life cycles of the pests and their “preferences,” and developing new and creative control measures and eradication techniques, and consumer education programs.

In addition to the usual insecticides, fumigants, repellents, contact sprays and mothproofing agents, creative chemists are working on “antimetabolites” which disrupt the insect’s metabolic cycle, insect growth regulators (IGRs), chemicals that control insect behavior, and biological controls through microbial pathogens that attack the insect population with bacteria or fungi, harmless to higher animals and humans, but devastating to specific insects. Some have proposed using electromagnetic, sonic and ultrasonic radiation, gamma radiation, microwaves and radio waves for insect control.

Most people are quite aware of clothes moths and the damage they can cause, thus the term “moth-eaten.” However, the moths are just one of the top three causes of all insect damage to fabrics. The other two are carpet beetles and silverfish. References to insect damage date from very early times. There’s a biblical reference in James 5.2 “Your clothes are moth-eaten.” In 400 B.C. it’s reported that Aristophanes said, “Moths were eating the feather plumes of helmets.” Actually, that term should be “larvae-eaten,” because the adult moths have imperfect mouth parts and can’t eat anything, which we’ll mention further under their life cycles below.

Carpet beetles cause extensive damage, too! One of the big differences is that moth larvae will stay put with their food source (your fine clothes) whereas carpet beetle larvae enjoy traveling from one room to the next, from one apartment to another, and have even been found in bird and rodent nests!  Knowing which insect is doing the damage will help you find and eliminate an infestation.

 

 

 

Primary Types of Insect Damage

Direct Insect Damage

Direct damage is caused by insects that feed directly on the fabric of your garment. They are especially attracted by leftover smells of food stains and body oils. Common examples are webbing clothes moths, casemaking clothes moths, carpet beetles, and sometimes termites. Damage done by silverfish is actually in the “indirect damage” classification (see below). Even if damage appears to be limited to a closet, don’t assume the culprit is clothes moths. If you don’t see moths flying, pupa casings, cocoons, or larvae, carpet beetles could easily be the problem. Once they feed they often migrate, leaving behind only the damage.

While feeding on the fabric the insect cuts or weakens the surface fibers. Often the damage is not even noticeable until after an article is dry cleaned or washed. During cleaning, the weakened fibers are flushed away, leaving damage visible on the garment. In addition, discoloration to the fabric may be caused by the insect’s droppings.

Insect damage occurs on any fabrics containing natural, cellulose, or animal fibers, including blends of wool/synthetic and cotton/wool, wool, mohair, silk, cotton, leather, natural bristles, fur (beaver, mink, seal and angora rabbit), feathers, down and even piano felt and natural bristle brushes. This includes the specialty fibers made from camel hair, alpaca, llama, guanaco, vicuna, and cashmere. Be especially cautious of articles left undisturbed for a long time, such as old military uniforms, blankets, feathered hats, tuxedos, overcoats, evening gowns, hats, antique dolls and toys, and wall hangings.

Don’t think that by using a synthetic blend that insects will stay away! Synthetic blends with as little as 10% natural fibers are not immune to insect damage. These synthetic fibers may contain residues of gum and sizing from processing, which is very attractive to insects. Some studies have found the most damage could be done to 35/65 wool/polyester and the least to 30/35/35 wool/acrylic/polyester fabrics.

What it Looks Like

Direct damage looks like tiny holes, veins or burrows in the surface of the fabric or knit. When you see this type of damage you can be fairly certain your garment has been serving as a main course for some growing larvae!

Indirect Damage

A different type of damage, “indirect damaged,” occurs when insects feed on spilled food or perspiration on the fabric. The “trails” of indirect damage follow the direction of food or beverage spills. Common examples of insects that do indirect damage are: silverfish, crickets, beetles, and roaches. Most of them feed on natural starches and glues, leaving visible damage (but not holes) on finer fabrics such as silk, cotton, linen and rayon.

What it Looks Like

Indirect damage generally leaves “trails” on the surface of the fabric. Silverfish, for example, eat at the surface leaving a “shaved” look, but will usually not leave actual holes in the fabric. They’ll do more damage to your books than your textiles!

Habits – Lifestyle, Appearance & Evidence

General Habits

Adult insects deposit their eggs in all sorts of locations—clothing, upholstery, rugs, toys, animal skins, trophies, and even natural bristle brushes. They prefer to feed in areas that are dark and undisturbed such as closets, attics and storage boxes. Things in constant use or frequently vacuumed, rarely get damaged, but watch those unused areas of a rug next to walls or under furniture! Even air ducts are a popular breeding area! As the eggs hatch, the larvae will look for any animal-based material to feed on: silk, wool, leather, dog and cat hair, feathers, and even wool blends or synthetics that may contain food stains, urine, hair oils, sweat or body oil residue.

The eggs and larvae, as well as adult insects, enter your home in a wide variety of ways – on your clothes, pets, shoes or they may fly in through an open door or window. Articles containing wool or other animal fibers, upholstered furniture, woolen fabrics and rugs are popular avenues. Be especially wary of used clothing or furniture, and items purchased at antique stores, vintage stores, yard sales or on-line auctions.

Adult clothes moths prefer darkness and hide very quickly if disturbed. They are definitely NOT the moths you see attracted to lights! Clothes moths are light tan, about 1/2” long and have very narrow wings. Adult carpet beetles, in contrast, love the sunlight and are known to feed outdoors in your garden on the pollen and nectar of flowers, especially Spirea, asters, dahlias, daisies, sunflowers, Virburnum, Caeothus, goldenrod and the flowers of wild and cultivated fruits. They’ll enter your house with these blossoms, or fly through an open window or door! The most common ones are small, oval-shaped and mostly black with varied patterns of orange and white. Carpet beetles are often mistaken for a common garden “lady bug,” but they are about 1/4 to 1/2 the size.

Silverfish, a primitive-looking 1/4” long, silver-colored wingless insect, is probably related to something that crawled up on land 300 million years ago. In North America they are almost exclusively associated with human habitation, and reside in houses and stables. They are quite prevalent in kitchens and bathrooms, for they require very high humidity or access to water. They thrive on the tiniest scraps of food. Although they prefer starchy food, they are quite able to digest cellulose and will devour your books and Christmas decorations as eagerly as the food stains on your garments!

Life Cycle, Appearance & Evidence

Webbing Clothes Moths (Tineola bisselliella)

Probably more common than the casemaking clothes moth, the Webbing Clothes Moths spin a silken web to form feeding tubes, which they attach to the items being eaten. The body of the adult moth is covered with shiny, golden scales and the top of its head has a tuft of fluffy, reddish-gold hairs. It has black eyes, its antennae are darker than the rest of its body, there are no spots on its wings, and females are slightly larger than the males. The female lives about 15 to 30 days and lays 40 to 50 large eggs (relatively speaking, 1/24” long). The eggs are translucent and quite vulnerable to physical damage. Her nest may be very hard to spot as she will lay a layer of camouflage web or casing over the eggs and developing larvae that blends into its surroundings, hiding it in the fabric. Look for webbing, cocoons, cases, copious amounts of tiny pellets, and even dead moths clumped into the webbing. In addition, the droppings may be the same color as the fabric being consumed, making the evidence even harder to spot. This “nest” may look like a harmless piece of lint.

Depending on the temperature and season, the eggs hatch into larvae in 4 to 30 days. These worm-like larvae are shiny, creamy-white and about 1/2” long when mature. The larvae spin silken feeding tubes as they feed, and reach maturity in 35 days to 2.5 years. This great variation in time is dependent on food, temperature and humidity. In a warmer climate, the clothes moth larvae live for at least two months. The perfect environment for clothes moth development is 75% relative humidity in a heated, dark room. The adults don’t eat, so larvae must consume enough so the adults may complete their life-cycle. The larvae change to a pupa and live inside silken cases they make as they mature into adults. This pupal stage may last from 55 days to as long as 4 years! Under normal conditions it’s usually from 65 to 90 days. The adult emerges from the pupa to start the life cycle again, generally about 2 generations per year.

Casemaking or Case-Bearing Clothes Moths
(Tinea pellionella)

Casemaking or case-bearing clothes moths are slightly smaller than the webbing clothes moths. The adult is light brown with 3 barely visible dark spots on each wing. The adults live for only 4 to 6 days. The females lay 37 to 48 creamy-white oval-shaped eggs (photo on left), which soon turn red, and hatch in 4 to 7 days into larvae which look like cream-colored caterpillars less than 1/2” long. During the larval stage, which lasts 68 to 87 days, they spin protective cases (using bits and pieces of items they’re consuming!) and drag the cases along as they move (it’s an “insect RV”!). (Below: Larvae & cases) Eventually the cases become the tough cocoons in which the pupae develop into adult moths in 9 to 19 days. Evidence of their presence is similar to the webbing clothes moths. Other less common moths include the Brown House Moth, and the Tapestry Moth, both of which require at least 80% humidity to thrive.
 

Carpet Beetles (Anthrenus verbasci & Attagenus pelio)

Carpet beetle adults live 20 to 60 days. The female lays 30 to 100 eggs on a surface sure to provide good nutrition for the growing larvae. Those larvae hatch in 6 to 20 days and live 60 to 325 days. The pupal stage lasts 10-17 days. The average life is about 9 months! Carpet beetle larvae measure 1/8” to 1/4” long and appear to be densely covered with tiny hairs or bristles.

They molt several times during their life cycle, leaving behind skin casings, which look a lot like larvae. Their droppings look like a uniform powder made up of tiny granules the color of whatever they’ve been eating. They do not spin webs, nor make cocoons like the moths. They tend to burrow deep into carpets and may not always be obvious. As they mature, they shed their skins and then crawl from place to place. They are often found in areas that don’t provide food for them. Their fecal matter, however, is generally found where they’ve been eating. Both the larval and adult stages damage fabric and also feed on seeds, pet food and cereal products in your kitchen and pantry, as well as flowers in your garden. The adults measure 1/10” to 1/3” long. They’re oval shaped and vary in color from shiny black to various patterns of white, yellow, brown and orange.

Silverfish (Lapisma saccharina)

Silverfish are small wingless insects that do not have larvae in their life cycle. They lay eggs which hatch into nymphs that look like miniature adults. They molt several times as they grow, leaving their cast skins to detect. Both adults and nymphs damage fabrics. They love moisture (75 to 97% humidity), cool to moderate temperatures (70 to 80° at the most), and dark places. They tend to be most active at night, and feed on starch, sugars and proteins. You’ll find them in sinks and bathtubs because they enter looking for the moisture and then get trapped, unable to climb the slick, vertical walls. They also love rayon and the glue found in book bindings and wall paper. The presence of silverfish indicates a moisture problem, but they can survive long periods of dry conditions and starvation. Infested areas should be aired out and dried. They live for quite a long time compared to the moths and carpet beetles, sometimes as long as 5 to 7 years, but they are also not very prolific. A female will only lay about 20 eggs in her lifetime, depositing them in tiny cracks and crevices. The eggs hatch in 19 to 43 days and mature from hatching to adult in 3 to 4 months. The droppings of silverfish look like very fine black pellets, somewhat like miniature mouse droppings, scattered over the surfaces in dark areas where they reside. They may leave yellow stains, especially on linens.

Lifecycles of Moths, Silverfish & Carpet Beetles

 

Why Insect Damage Happens

Clothes are usually stored in dark, warm places. Insects and their larvae have a wonderful opportunity to feed undisturbed. The amount of damage that occurs is in direct proportion to the temperature and humidity in the storage area. Warm, moist areas are the ideal growing condition for insects!

Most damage occurs during the larval stage of the insect’s growth. That is also when they need the most food. The adults naturally gravitate to areas of your house that contain everything they need: a food source consisting of fabrics with remnants of stains or soil, warmth, and moisture.

Examples of poor areas to store clothes: closets with exterior walls, garages or basements with concrete floors, and nice warm attics.








 

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