Why Does the Webbing Clothes Moth Make PMPs Cringe?

What is it about the webbing clothes moth that makes pest management professionals cringe and groan? Why does this little monster elicit such disdain? Is it the infrequency of calls, their lengthy life cycle, all the weird things they can feed on, the high cost of service to get to complete elimination, the labor-intensive prep that’s required, or the type of customer involved? How about “all of the above?”

With the right education and mindset, we can turn your clothes moth frown upside-down. Control requires extensive knowledge and thorough inspection. It’s not a one-and-done type of service, and you don’t accidentally solve the problem with a simple baseboard spray. Control is only achieved through deliberate efforts driven by your deep understanding of this pest. Many pest control operators would walk away from a clothes moth job… but not you. You want the challenge and the satisfaction of winning. In order to achieve this, though, you need to know your foe.

I’m an entomologist so I have to say it: identification is always the first step. The webbing clothes moth is a tawny, narrow-winged moth with feathery fringes at its tips. The head is adorned with a fabulous reddish-orange pompadour. Size wise, this moth is smaller than the Indianmeal moth. The caterpillar or larval stage is pale with an orange head. Neither the adult moth or caterpillar have patterns or markings—just a solid-colored body with an orange noggin.

Over-the-counter pheromone traps are regularly used by homeowners to detect clothes moths. Keep in mind that not all captures on a clothes moth trap will be a webbing clothes moth! Varied carpet beetles and other scavenger moths are common victims to these traps and may indicate different problems, like desiccated rodent carcasses or bird nests in chimneys. These traps may also catch casemaking clothes moths, a less-frequently-encountered species that causes similar damage and requires similar treatment as the webbing clothes moth.

Like their butterfly relatives, clothes moths develop through complete metamorphosis. They are born into the world as eggs, hatch out into ravenous caterpillars, weave themselves into silky cocoons once they’ve eaten their fill, and transform themselves into flying adult moths—the life stage most people notice first.

© credit | Natasha Wright

The adult moth, with a mouthpart resembling a curled straw, is incapable of doing more than slurping up liquids. The only life stage that causes damage is the caterpillar. Their mandibles can chew through fibers with ease. Wool rugs often have bald spots while clothes and blankets may have holes . The caterpillars spin silk and leave webbing in the wake of their feeding activity. Their fecal material resembles sand or dirt on otherwise clean material. 

Tiny pin holes found in clothing are not enough to diagnose a clothes moth issue. Holes could be caused by normal wear and tear, mechanical damage, or other pests like carpet beetles and silverfish. I used to wonder why I had numerous small holes at the bottom of my tee shirts; it turns out that my belt buckle would rub against the shirt fabric when I leaned against the counter to wash dishes. Customers may have their own tasks or daily rituals causing fabric damage to occur.

Wool is the favored food of the webbing clothes moth, and wool is simply animal hair. Get used to the feel of wool in all of its forms. Touch everything during your inspection. If you are unsure of the material you have, check the tag. Look for wool, cashmere, and wool blends. Clothes, blankets, and rugs will be your chief items of concern, but don’t neglect other animal-based items: pelts, taxidermy, mohair bears, antique or vintage dolls, items with leather or wool lining, military uniforms, historical flags, piano felts, felt-lined silverware/jewelry/gun boxes, crafting material like wool yarn, or accumulations of pet hair. These moths are especially fond of unwashed woolens or anything saturated with sweat, skin oils, or urine. 

Some oddball sources that I’ve encountered include deer mouse carcasses, a felt-lined drawer in a buffet table, the felt of a pool table, and a leather baseball mitt and real-fur teddy bears that previously belonged to a deceased child. In a normal home, a ragged mitt might be thrown away and the teddy bears tossed into a washing machine. Show compassion to your customer by handling sentimental and irreplaceable items with love and care.

© credit | Natasha Wright

World travelers and the wealthy suffer most from clothes moths. Handmade or collectible treasures from other parts of the world are often crafted from wool. A resident at an assisted living facility had a wool wrap from Mexico that was coiled up beneath a lamp. At a glance, it seemed in good condition, but the silken strands and fecal pellets of feeding caterpillars were hidden from view by the base of the lamp. Oriental and Persian rugs, cozy cashmere sweaters, and other wool-based luxury items are commonplace in the homes of the prosperous. The average person’s wardrobe and furnishings are an amalgamation of synthetic materials which are not appealing to the clothes moth.

Eliminating a clothes moth infestation is an endeavor that requires cooperation from the customer and diligence from the pest control operator. The process is long and the steps are many. Your relationship with the customer will be complicated as they simultaneously love you and hate you for what you make them go through. Are you both prepared for what is to come?

We, as pest control operators, need to understand that these moths have long life cycles. The average time it takes to go from egg to adult moth is anywhere from 60 to 90 days. Use pheromone traps to monitor for the adult moths and place them throughout the home to pinpoint areas of concern. If you can go 60 to 90 days without a capture on any of your pheromone traps, then you’ve most likely broken the life cycle and treated or removed all potential food sources. If you do get a capture on a pheromone trap, you should reinspect and retreat in the general area and proceed to reset your “timer” until you can go 60 to 90 days without another capture. How long you want to wait is up to you, but it shouldn’t be shorter than 60 days.

You will need to explain to the customer that there is a great deal of prep work on their end, and there is no way around it. There is no magic wand that we can wave to relieve the customer of effort. We can handle the big stuff—like their obscenely large rug held down by numerous pieces of solid wood furniture—but only they can take care of the alpaca-wool sweaters and mink coats lining the walls of their walk-in closets. These smaller susceptible items must be dry cleaned, decontaminated, or somehow rendered moth-free, and stored in such a way as to prevent infestation during the treatment period. Items may need to be stored offsite, at a relative’s house (who doesn’t have moths), or in airtight containers. These items must remain tucked away until the treatment is complete. This can be a long time, especially when customers demand immediate results and a return to normalcy. The moths must be deprived of all available food sources (that can’t be treated with insecticides) until their population crashes. 

Items that can’t be safely washed and dried can be frozen for three days at -22°F, a week at -13°F, and two weeks at 0°F (Pinneger, D. 2001). A medium-heat dryer cycle for 45 minutes will ensure the death of all life stages.

At some point in your clothes-moth-treating adventures, you will have to treat rugs. Be sure to choose an insecticide labeled for general surface application. Insecticides that only permit spot applications will not be suitable for area rugs.

Leave enough time for treatment. You might need two people or you might need six. Your customer might reside in a single-family home, or they might be living the good life in a castle with two guest houses. Picture a massive rug covered by couches, glass coffee tables, and plush rocking chairs. If you want your treatment to be as effective as possible, you should move furniture and treat both sides of the rug. It’s a hassle, but elimination is heavily dependent on your thoroughness. You can incorporate this extra time into the cost of your service.

In time, you will struggle with a lingering clothes moth problem. It is bound to happen. Pheromone traps will help you isolate areas of concern. If you place pheromone traps in every area of a house, and you are still capturing moths on the trap in the attic, then there is a source, in or near the attic, that you have missed. I was faced with this situation before. A coworker and I offered to help move some bagged clothes downstairs for the customer since it would have taken her an eternity to do alone. All of the clothes were made of synthetic material, which we documented during our initial inspection. However, behind the bags of non-attractive fabrics, there was a hidden source — a small wool rug, lost to time and memory, that was completely decimated by clothes moths.

You will have clothes moth jobs that are easy, some that are hard, some that are frustrating, and some that are downright impossible (depending on how much cooperation you get from the customer). Don’t lose your confidence after a control failure. Your victory over these moths is dependent upon your vast knowledge about their life cycle, their food sources, your meticulousness during inspection and treatment (and retreatment), your education of the customer and what they should expect, and your determination in seeing it through until the end. The more you immerse yourself in clothes moths, the better you’ll get at annihilating them. 

References:

Pinniger, D. 2001. Pest management in museums, archives, and historic houses. Archetype Publications Limited, London, England.