What's "Bugging" You, Insect Damage to Textiles
In This Issue...
What’s “Bugging” You? — Part 1 of 4
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.
Continued from Introduction...
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!
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!
Continued in Part Two: Habits — Lifestyle, Appearance & Evidence