Clothes Moth Management
By Ethan Estabrook, BCE, Research Entomologist and Product Support, Insects Limited
Webbing clothes moths belong to the family Tineidae which contains over 3,000 species and is collectively known as the clothes moth or fungus moth family.
Many moth species in the Tineidae family look very similar to one another. In many cases, proper identification requires dissection of the abdomen to view the genitalia structure to determine the exact species.
Mark Metz with the USDA used this technique to determine a new species of clothes moth Niditinea sabroskyi, which has been historically misidentified as the brown-dotted clothes moth, Niditinea fuscella.
Clothes Moth Identification
Luckily webbing clothes moths can be identified by their appearance and without dissection. Webbing clothes moths can be identified by their single tone of creamy white to shiny gold coloration with no spots. They have a tuft of hair-like scales on their head that are usually golden to reddish brown. They vary in length from 5–8mm with a wingspan between 9-16mm. The wings are held at a tent-like angle over the abdomen when at rest. The antennae are threadlike and about three-quarters the length of the hindwing. T
The casemaking clothes moth, Tinea pellionella, is another economically important clothes moth species. The casemaking clothes moth can be differentiated from the webbing clothes moth by their darker brown wings with spots. Webbing clothes moths got their name by the webbing the larvae spin. Larvae will produce crude tunnels where they mesh together food particles, fecal pellets, and cast skins with the webbing they produce. This behavior is different from the casemaking clothes moth larvae who produce a portable protective case that they carry with them.
Clothes Moth Life History
Webbing clothes moths can complete their life cycle on average 50 – 150 days depending on temperature, humidity, and food availability. Clothes moths who have more favorable conditions complete their life cycle at a quicker rate which allows populations to grow exponentially causing infestations, product damage, and contamination. Conversely, unfavorable conditions slow down the clothes moth life cycle which allows some of the insect life stages to live for a longer period but reduces the risk of infestation. Webbing clothes moth adults live for 15-30 days whereupon mated females can lay 40-50 eggs individually or in groups. Eggs hatch in 4-10 days in warmer months and up to 30 days in cooler months. The larvae then feed and become mature in 35 days or as long as 30 MONTHS depending on food quality, temperature, and humidity. Pupation will occur in infested materials and emerge as adults in 8 to 40 days depending on temperature. In unfavorable conditions and poorer diets such as feathers and human hair, development can take OVER A YEAR OR TWO to be completed.
When looking for signs of clothes moth infestations, look for the granular frass the size of ground pepper or white webbing tunnels on or around items they are suspected to be feeding on such as fabric, furs, taxidermy mounts, hanging clothes in closets, wool rugs, carpets, and upholstered furniture when rips or tears expose stuffing.
Pheromone lures and traps can be used to monitor webbing and casemaking clothes moth activity. Pheromone monitors provide very useful information about insect activity, such as the detection of insects, insect species, population trends, and locations of infestations.
Pheromones for Clothes Moths
The chemicals produced in a clothes moth pheromone lure have compounds that attract the males of both webbing clothes moth and casemaking clothes moth. This pheromone lure mimics the natural compounds that female moths emit when attracting a male mate. Because of this interaction, pheromone lures will only attract male moths and will not attract females. Pheromone lures elicit a behavioral response, and you cannot depend on that behavioral response to catch all males in a population. Some males may not be actively looking for a female to mate with, or there may be competing pheromone trails with other female clothes moths that lead a male away from the pheromone lure. Wind direction could also be interfering with the pheromone plume making it difficult for the male to find a lure. It is important to use pheromone lures as a detection and monitoring tool. Once clothes moths are detected the goal is to figure out where they are coming from. You can use pheromone lures to help identify suspect areas where more moths are captured. Once you determine a suspect area, inspect items that contain wool, fur, or feathers. These items are more than likely the food source of clothes moth larvae.
Locating the Source Clothes Moths are Feeding On
I think it is important to share some of our experiences of what we have seen clothes moths feeding on. This may help you better identify where the source of clothes moth activity is coming from and ultimately allow you to manage and control these insects. I have broken down items into four different categories to be on the lookout for:
Wool, Fur, Feathers, and Miscellaneous.
For wool, inspect wool or Persian rugs and wool carpet padding. Wool clothes including sweaters, jackets, hats, suits, and socks. Wool blankets. Wool wall decorations like macrame, tapestries, and Native American artwork. Upholstered furniture containing wool especially if the furniture has tears or is damaged. Wool yarn. And even piano hammer felt on the inside of pianos.
For furs, inspect taxidermy, animal hide rugs, and fur clothing. Accumulations of pet hair and human hair especially in undisturbed areas where they have been able to accumulate over time. Horsehair plaster, which was a common practice in older, historic homes. And dead animals such as a mouse or squirrel that may have died in a wall void, crawl space, or beneath wooden floors.
For feathers, inspect taxidermy birds, feather or down comforters, pillows, sleeping bags, or quilts especially ones with tears or openings. Feathers incorporated into artwork including Native American art, contemporary art, or children’s art. Bird nests or a dead bird inside wall voids, garages, crawl spaces, or ceiling voids. And organic fertilizers like feather meal, which is actually what we feed our clothes moth colonies.
And finally, for miscellaneous, inspect areas with accumulations of dead insects like windowsills or window vents. Cricket powder or flour can be suspect, which has become more popular in baking. Dried insects which are used as bird or reptile food. And pet toys that include items like horns, hoofs, and antlers.
Treatment
Isolating and bagging an item can further help identify if clothes moth activity is present. Place the suspect item on white paper in an airtight polyethylene bag. After a couple of weeks, inspect for signs of of insect activity such as live insects, cast skins, frass, or webbing on the white paper or at the bottom of the bag.
Once you identify the source of a clothes moth infestation or a suspect item they may be feeding on, there are several ways to treat it. Washing and drying clothes on high heat and then storing those clothes in an airtight or the GreenWay Moth-Resistant Garment Bag, can help prevent future clothes moth infestations on clothes.
Consistent disturbance by vacuuming areas where clothes moths are suspected to be will not eradicate moths, but help reduces potential food sources like pet and human hair which will ultimately reduce populations.
Storing items in a freezer for 7 days will kill all clothes moth life stages. Products like the GreenWay Freezer Bag can help protect items during a freezing treatment. Increasing heat to 130-140 degrees Fahrenheit for 3 hours will also kill all clothes moth life stages. This could be as simple as storing suspect items in a hot car during the summer, purchasing a solar bag like ZappBug from Amazon, or teaming up with a pest management professional to bring in industrial heaters to perform a heat treatment on a room of a house.
Anoxic treatments are another option that adjusts the atmospheric gases and reduces oxygen concentrations to below 1% for 21 days. Anoxic treatments are common treatments for museum artifacts and require airtight control chambers.
Fumigation can also be used to eradicate all life stages in the shortest amount of time but is also the most dangerous and expensive means of treatment. Fumigation involves teaming up with a pest management professional and using products like phosphine at 500 -1,000 parts per million for 72 hours when temperatures are above 70 degrees Fahrenheit. Sulfuryl fluoride can also be used at around 500 – 1,000 CT for 24 hours when temperatures are above 80 degrees Fahrenheit. There are also other pesticide options such as pyrethroids, insect growth regulators, organophosphates, boric acid, or diatomaceous earth that can be used to treat clothes moths. Make sure to read and follow the label when using any type of pesticide.
It is important to Start with the Insect First!
Identifying the clothes moth species and understanding their biology is the first step to an effective integrated pest management program.
Once the clothes moth has been identified, inspect areas for ideal food sources such as wools, furs, or feathers.
Pheromone lures and traps are great tools to monitor and help identify the source of infestation.
Finding and treating the source can help pest management professionals solve a difficult pest problem to help protect household items like your favorite wool sweater to museum artifacts of historical importance.
If you have any clothes moth or pheromone questions, you can contact me at E.Estabrook@InsectsLimited.com.
Insects Limited, an Insect Pheromone Company
Insects Limited, Inc. researches, tests, develops, manufactures and distributes pheromones and trapping systems for insects in a global marketplace. The highly qualified staff also can assist with consultation, areas of expert witness, training presentations and grant writing.
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