Moths, often mistaken for butterflies, play a vital role in our ecosystem as pollinators and a food source for various animals. However, they can become a nuisance when they invade our homes. Understanding what moths eat is crucial for preventing damage to our belongings.
The Moth Life Cycle: A Matter of Larval Consumption
It's a common misconception that adult moths are the culprits behind damaged clothes and pantry items. In reality, the larval stage, when the moth is a caterpillar, is when the real eating happens. Adult moths of many species don't eat at all, using the energy they stored as caterpillars to focus on mating and laying eggs.
The female moth strategically lays eggs near a prime food source, whether it's flour in a pantry, sweaters in a closet, or leaves in a forest. Depending on the species, the eggs might end up on various materials.
Moths go through four stages, each impacting your property and belongings differently:
- Egg: Female moths lay eggs on suitable food sources.
- Larva: The larval stage is when moths do the most damage, feeding on the material where they hatched.
- Pupa: In this stage, larvae transform into adult moths.
- Adult: Adult moths primarily focus on reproduction and do not cause significant damage.
Pantry Moths: Targeting Stored Foods
If your kitchen has become an all-you-can-eat buffet for fluttery guests, you might have a pantry moth infestation. These moths, such as the Indianmeal moth, Mediterranean pantry moth, or almond moth, lay their eggs in stored foods, including kibble bags.
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Pantry moths, also known as grain moths, weevil moths, or flour moths, consume raw or processed grain products. They feed on items like cereal, flour, oatmeal, baking mixes, pasta, beans, nuts, dried fruit, spices, tea, chocolate, and candy.
Clothes Moths: A Wardrobe Nightmare
Not all moths go for your pantry; some aim for your wardrobe. Clothing moths, like the common clothes moth (aka webbing clothes moth) and casemaking clothes moth, lay eggs in dark, undisturbed places with plenty of natural fibers. The brown house moth and white-shouldered house moth are other common invaders.
Clothes moths are pests that can destroy fabric and other materials. They feed exclusively on animal fibers, especially wool, fur, silk, feathers, felt, and leather. These materials contain keratin, a fibrous protein that the worm-like larvae of the clothes moth can digest. In nature, the larvae feed on the nesting materials or carcasses of birds and mammals.
Cotton and synthetic fabrics such as polyester and rayon are rarely attacked unless blended with wool or heavily soiled with food stains or body oils.
Identifying Clothes Moths
Clothes moths are small, 1/2-inch moths that are beige or buff-colored. They have narrow wings fringed with small hairs. They are often mistaken for grain moths infesting stored food items in kitchens and pantries. Unlike some other types of moths, clothes moths are seldom seen because they avoid light, preferring dark, undisturbed areas such as closets, basements, and attics.
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Two different types of clothes moths are common in North America: the webbing clothes moth (Tineola bisselliella) and the casemaking clothes moth (Tinea pellionella). Adult webbing clothes moths are a uniform, buff color, with a small tuft of reddish hairs on top of the head. Casemaking clothes moths are similar in appearance but have dark specks on the wings.
Clothes moth adults do not feed, so they cause no injury to fabrics. The larval stage of clothes moths are creamy-white caterpillars up to 1/2-inch long. Development time before transforming into a moth varies greatly (from one month to as much as two years), depending on temperature, food availability, and other factors.
Webbing clothes moth larvae spin silken tubes or patches of webbing as they move about on the surface of infested materials. They often feed within folds of fabric and other concealed areas. As larvae graze along the surface, threadbare spots occur where fibers are removed at the base. On animal (taxidermy) mounts, clumps of hair will often detach from the skin. The casemaking clothes moth encloses itself in an open-ended tubular case, which it drags about wherever it goes. Incorporated into the silken case are fibers from materials the larva has fed on. Unlike the webbing clothes moth, casemaking clothes moths seldom incorporate webbing or cocoons into the materials on which they are feeding.
It is important to recognize that damage attributed to clothes moths may in fact be caused by another group of insects adapted to digesting keratin-carpet beetles. Carpet beetles are very common in homes and buildings and feed on most of the same materials as clothes moths. However, these pests are quite different in appearance.
What Clothes Moths Target
As noted earlier, clothes moths feed on such animal-derived materials as wool, fur, silk, feathers, and leather. Articles commonly infested include sweaters, scarves, coats, blankets, rugs, down pillows and comforters, upholstery, toys, decorative items, and taxidermy mounts. The larvae prefer to feed in dark, undisturbed areas such as closets, chests, and boxes where woolens and furs are stored for long periods. Clothing and blankets in regular use are seldom infested, nor are rugs that get a normal amount of traffic or are routinely vacuumed.
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Clothes moths may also be found infesting upholstered furniture (both inside and out) and in vents and ducts where the larvae may be feeding on lint, shed pet hair, and other bits of debris.
Recognizing Signs of Moth Infestation
To protect your belongings from moths, it's essential to recognize the early signs of a moth infestation. Here are some indicators to watch for:
- Damaged Fabrics: Holes in clothing, blankets, and upholstered furniture are a clear sign of fabric-eating moths. These pests prefer dark, undisturbed areas like closets and storage rooms.
- Webbing and Silk Cocoons: Look for webbing and silk cocoons in your pantry and around your home’s fabrics. These are indicators of moth larvae, which cause the most damage.
- Sightings of Adult Moths: While adult moths do not cause damage, seeing them in your home is a sign that you may have a more significant problem. If you see adult moths, it often means there are multiple generations, which leads to a more severe infestation.
Preventing and Controlling Moths
Prevention is the best way to protect your home from moths. Here are some effective strategies:
- Regular Cleaning: Moths can infest any home, regardless of cleanliness. They are attracted to natural fibers and food sources, not dirt or grime. However, frequent cleaning can disrupt moths’ life cycles and remove potential food sources. Vacuum your carpets, rugs, and upholstered furniture regularly, paying special attention to dark, undisturbed areas where moths may lay eggs.
- Proper Food Storage: Store your pantry items in airtight containers to prevent pantry moths from accessing your food. Regularly check your pantry for signs of infestation and dispose of any contaminated items in exterior trash receptacles.
- Use Moth Repellents: There’s some anecdotal evidence that natural repellents like cedarwood, lavender, and cloves may help to deter moths. Place these items in your closets and storage areas to keep moths at bay.
- Professional Pest Control: If you have a severe moth infestation, consider hiring a professional pest control service. They can provide targeted treatments to eliminate moths and prevent future infestations.
- Homemade Moth Traps: Create homemade traps using sticky tape and attractants like pheromones. These traps can catch adult moths and perhaps reduce their population, but mainly to identify high population areas.
- Freezing Infested Items: For fabric moths, freezing infested items can kill larvae and eggs. Place the affected items in a plastic bag and freeze them for at least 72 hours.
- Vinegar Solutions: Wipe down shelves and storage areas with a vinegar solution to remove moth eggs and larvae. Vinegar can also repel adult moths.
Additional Control Measures
Controlling clothes moths requires a thorough inspection to locate all infested items. The primary source may be a wool scarf or fur/felt hat at the back of a closet, an old rug stored in the basement, or an abandoned bird or squirrel nest up in the attic. Larvae prefer to feed in dark, undisturbed areas where woolens and other susceptible items are stored for long periods.
When inspecting clothing, pay attention to seams, folds, and creases. Larvae also may be found along and beneath edges of rugs and carpeting. Use needle-nose pliers to lift the outer edge of wall-to-wall carpet from the tack strip along baseboards. Other possible locations include beneath/within upholstered furniture or inside heat ducts and floor vents with accumulations of pet hair and lint.
Infested items and susceptible articles nearby should be laundered, dry-cleaned, or discarded. Bagging heavily infested items before disposal can help prevent further spread of the moths. Dry-cleaning or hot laundering kills any eggs or larvae that may be present. Heat generated by a clothes dryer is effective as well.
Vacuuming floors, carpets, and inside heating vents effectively removes larvae as well as hair and lint, which could support future infestations. Insecticides applied to infested rugs and carpets may be helpful as a supplement to good housekeeping. Sprays recommended for flea control or with fabric insects listed on the label are effective. When treating, pay particular attention to carpet edges, floor/wall junctions, beneath furniture, and bottoms of closets. Infested clothing or bedding should not be treated with insecticides.
Woolens and other susceptible items should be dry-cleaned or laundered before being stored for long periods. Cleaning kills any eggs or larvae that may be present and removes perspiration odors that tend to attract pests.
Householders intending to use moth-deterring balls, flakes, or crystals should carefully read and follow label directions. The volatile, odiferous products containing naphthalene or paradichlorobenzene can be hazardous if used incorrectly. Never scatter them in open closets or other areas where children or pets can reach them. The vapors from these materials are only effective if maintained at sufficient concentrations.
Valuable garments such as furs can also be protected from clothes moths by storing them in cold vaults, a service offered by some furriers and department stores.
Detecting Infestations in Museums and Other Institutions
Museums, rug dealers, craft shops, furriers, and taxidermists have much at stake in preventing clothes moths. Museum artifacts, in particular, can be irreparably harmed by these pests, making prevention a necessity. To minimize risk to collections, vulnerable items should be routinely monitored for signs of moth activity. Objects on display and in storage should be closely examined for holes, ‘grazed’ areas, detached hair, fur, or feathers, webbing, fecal pellets, larvae, or adult moths.
Glue traps provisioned with a pheromone lure are also useful for detecting infestations. The lure mimics the sex pheromone of the female clothes moth and is highly attractive to the males. The traps are particularly effective at revealing infestations in the early stages when the pests are hard to find by inspection alone. Pheromone ‘baited’ traps may be placed on shelves, inside closets, or wherever susceptible items occur. In large storage or display areas, the devices can be installed in a grid pattern to help pinpoint infested materials, i.e., areas where a higher number of moths are captured tend to be closer to infested materials.
Thermal Disinfestation
Insecticide sprays tend to be of limited use for clothes moths since the pests are often within materials where sprays cannot penetrate. The risk of contamination and staining further negates their use on museum objects, clothing, etc. Such items can often be disinfested more effectively utilizing a household, chest, or walk-in freezer. In order to kill clothes moths, infested items need to be held at a minimum temperature of 0 degrees Fahrenheit for at least one week. Freezers capable of reaching minus 20 degrees F are able to kill all life stages within 72 hours.
Before freezing, articles should be placed in plastic bags or wrapped in polyethylene sheeting and sealed with tape. This prevents frost and ice from forming on objects during chilling and condensation after removal. After freezing, objects should be allowed to return to room temperature (for about 24 hours) before being unwrapped or further handled. Some items become brittle at low temperatures, and this will help to reduce breakage.
Beyond the Basics: Other Moth Diets and Behaviors
While pantry and clothes moths are the most common household pests, it's important to remember the vast diversity of moth species. With an estimated 160,000 species worldwide, moths exhibit a wide range of dietary habits and behaviors.
- Plant-Eating Moths: Many moth caterpillars feed on leaves, flowers, stems, and roots. Some are very particular, feeding only on a single plant species.
- Fungus and Lichen Feeders: Some moth caterpillars feast on fungi and lichens, making unexpected places like graveyards a buffet for them.
- Predatory Caterpillars: Some caterpillars even eat other caterpillars.
- Adult Moth Diets: Adult moths tend to feed on nectar from flowers, fruit, or sap. However, some adult moths don’t feed at all and don’t even have mouthparts.
Recognizing Moth Characteristics
Moths vary greatly in appearance and size. Some have narrow, swept-back wings for fast flight, while others have delicate, feathery wings. Some female moths have wings that are so short that they’re more like little nubs, and they don’t fly at all.
While most moth species are nocturnal, there are actually more species of day-flying moths in the UK than there are butterflies.
Moths and butterflies share the same basic biology and have far more similarities than differences.