Casemaking Clothes Moth

Name

Common Name:

Casemaking Clothes Moth

Scientific Name:

Tineola pellionella

Species:

pellionella

Genus:

Tineola

Family:

Tineidae

Order:

Lepidoptera

Class:

Insecta

Phylum:

Arthropoda

Appearance/Physical Description

Adult Casemaking Clothes Moth
Adult Casemaking Clothes Moth

The Case-making Clothes Moth is a species of tineoid moth in the family Tineidae, the fungus moths.  It gets its name from the open-ended, protective silk case that the larvae live inside and carry around when feeding.

Clothes moths have two distinct types: the webbing clothes moth, Tineola bisselliella, and casemaking clothes moth, Tinea pellionella. The webbing clothes moth is the most common fabric moth.

The casemaking clothes moth is similar in size and appearance to the webbing clothes moth, although the wings of the casemaking clothes moth are more brownish and have faint dark-coloured spots. Also, the hairs on its head are lighter coloured than those of the webbing clothes moth.

Appearance  differences Webbing Clothes Moth and Casemaking Clothes Moth

Larvae of both species are nearly identical, except the larvae of the casemaking clothes moth always carry a silken case with them as they feed. They never leave this silken case behind but enlarge it as they grow. They can feed from either end of the case and retreat into it when disturbed. This case takes on the colour of the fabric the larvae have eaten.  The webbing clothes moth larvae don’t carry around feeding cases but may produce patches of silk webbing.

They casemaking clothes moth larvae are often noticed when attached to walls or dragging themselves across smooth floor surfaces.

Excrement from both the webbing clothes moth and the casemaking clothes moth can contain dyes from the cloth fibres the moths have eaten, also making it the same colour as the fabric.  They are very small and not easily seen with the naked eye.

The adults are small (1cm), are silvery grey to shiny light brown in colour, with dark greyish hairs on the top of its head and and have a wingspan of 9 to 16 millimetres. Its forewings are grizzled brown with one large spot and a few smaller, indistinct black spots. The hindwings are plain pale brown grey. The forewings, but especially the hindwings are surrounded by a hairy fringe.

Actual size of Casemaking Clothes Moth

They are reluctant flyers and may be seen running over the surface of infested materials. Unlike many other moths, clothes moths are not attracted to light and avoid lighted areas.

Being a widespread species and often affiliated with humans, and T. pellionella was among the first moths to be scientifically described in the modern sense. At that time, most moths were included in a single genus “Phalaena“, but Tinea was already recognized as a distinct subgenus.  Some later researchers who studied this moth erroneously believed they had discovered populations formerly unknown to science and described them as new species, but today these are all included within T. pellionella.  

Habitatats / Harbourages

Clothes moths are found worldwide, including Australia, Asia, North America, and Europe.

Tinea pellionella are considered an insect of stored products. The food sources for this larval are wide varieties for examples the fur, hair, feather, wool, and small food particles including materials made from animal skins in the house.

A larva attaches to ceiling and walls of the buildings.  These insects are found both inside and outside walls of the house.  It is noted that any home having this insect, showed a cylindrical case on walls, house ceiling, kitchen floors, living room and bedroom walls.

Adult and larvae clothes moths prefer low light conditions. Whereas many other moths are drawn to light, clothes moths seem to prefer dim or dark areas.  If larvae find themselves in a well-lit room, they will try to relocate under furniture or carpet edges.

Handmade rugs are common locations due to the thick weave and ease of access for the larvae to crawl underneath and do their damage from below. They will also crawl under mouldings at the edges of rooms in search of darkened areas where fibrous debris has gathered, and which consequently contain high food sources.

Adults seek out tight spaces and can crawl through small cracks and openings to find appropriate food sources upon which to lay their eggs.

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. Infestations may also originate from bird nests or animal carcasses present in attics, chimneys or wall cavities.

They are usually found in homes because:

  • The eggs or larvae have been walked in by the inhabitants; or
  • They fly into the house in response to the scent of food; or
  • They have infested a birds nest or dead animal carcass in the roof cavity or sub-floor of the dwelling.

While the Tinea pellionella is naturally occurring in the wild their food sources are uncommon and disbursed which prompts them to track any available food source down; they can do this successfully from even the smallest scent.

Life Cycle

The Life Cycle of the Casemaking Clothes Moth

The beginning of the Clothes moth lifecycle – adult female moths can lay 40 – 50 eggs over their short life and these eggs are tiny, typically 0.5mm in length, which makes them almost invisible to the human eye.  Female moths lay eggs, singly or in small clusters. The eggs hatch from between 4 and 10 days depending on temperature and humidity. 

Casemaking Clothes Moth larvae emerging from egg

The eggs hatch as clothes moth larvae – this is the destructive stage.  Larvae develop through several stages (the casemaking clothes moth develops through 5 to 45 instars). 

The larvae are typically a few millimetres long upon hatching but then grow to 1 cm -1.5 cm in length, dependent on availability of food (i.e. your natural woollen and silk clothing or carpets as examples!) and moisture to help intake of water – they cannot ‘drink’ in a conventional sense and hence require humidity.  This is why residual perspiration or food and drink stains on clothing attract moths.

Fully mature larvae have white to cream coloured bodies with brown heads.  The casemaking moth larva has a singular ocellus (eye).  Larvae are found inside building cases or bags. When feeding, it will thrust out its head and can eat from either end of the casing. Moulting and pupations occur inside the casing.

Clothes moth larvae can stay at this stage for up to 30 months (2 ½ years!) happily eating your clothing or carpets whilst waiting for the right conditions to turn into adult moths.  This is precisely why clothing moth issues persist through the winter, not just from the Spring when the adults tend to start flying. 

Casemaking Clothes Moth Larvae on fabric
Cases from the casemaking clothes moth

When the temperatures are right and the larvae have reached the right size, they then start the pupation stage, spinning a cocoon in which they metamorphose into the adult moth.  This process typically takes 8 -10 days.   They pupate in the silken cases in which fibres from the infested fabric and excrement are incorporated.

The final part of the life cycle occurs when the adult clothes moth measuring about 1cm -1.5 cm emerges from the cocoon. Whilst relatively harmless in their own right, the presence of adult clothes moths signals a potential infestation should they be allowed to lay their numerous eggs.  The female adult clothes moth tends to hop or crawl – it is the male that flies more often in search of a mate.

Adults exist purely to mate and do not eat; females die within a few days of laying eggs, while males live approximately 1 month.

The life cycle may be completed within 2 months but may take several years.  In the wild, they may only have 1 or 2 lifecycles a year, however in a home, they may manage 6 or 7 lifecycles a year.

The larvae (caterpillars) incur damage to clothes and other household goods. 

Feeding Habits

Caterpillars of the casemaking clothes moths feed from within a somewhat flattened silken case which is dragged over the food source. Only their heads and legs appear outside, but they will eat from either end of the case.

Clothes moths are notorious for feeding on clothing and natural fibres; they have the ability to digest keratin. The moths prefer dirty fabric for oviposition (storage of eggs) and are particularly attracted to carpeting and clothing that contains human sweat or other liquids that have been spilled onto them.

They are attracted to these areas not for the food but for the moisture: the caterpillars do not drink water; consequently, their food must contain moisture. The range of their recorded food includes:

  • linen,
  • cotton,
  • silk,
  • wool fabrics,
  • furs,
  • leather,
  • lint,
  • shed feathers,
  • hair,
  • bran,
  • hemp,
  • tobacco,
  • semolina,
  • flour (possibly preferring wheat flour),
  • biscuits,
  • casein,
  • spices,
  • milk powders,
  • fish meals;
  • insect specimens in museums.

Household articles commonly infested include:

  • sweaters,
  • scarves,
  • coats,
  • blankets,
  • rugs,
  • down pillows and comforters,
  • upholstery,
  • toys, 
  • decorative items,
  • and taxidermy mounts.

Sometimes they will damage fabrics of plant origin and synthetic materials soiled with oils or blended with animal fibres.

The larvae prefer to feed in dark, undisturbed areas such as closets, chests, and boxes where woollens 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.  Edges and undersides of rugs, or sections beneath furniture are more likely to be attacked.

The adult moths do not eat, and live solely for the purpose of mating and laying eggs

Damage Caused

Often perceived as purely a household pest, clothes moths have been responsible for losses of industrial revenue exceeding millions in one year, although this has become less severe with a move away from natural fibres to synthetic fabrics.

Other species have however filled this vacancy, most notably fur and carpet beetles. 

Clothes moth has also been noted to infest dried vegetable material.

Control

As this species avoids light in all stages, they are located by examining stored animal product materials such as old clothing, woollens, yarn, furs, feather pillows and felt on piano strikers.

Regularly monitor fabrics and closets for clothes moths and their damage in order to take action when infestations are still small.

To inspect for clothes moths, look to see if there are silken tubes in the hidden portions of clothes, such as under collars, or silken mats or patches on material.   Also look in cupboards, on walls, under furniture and beside walls in carpeted rooms for any evidence of the caterpillar casings.

Both the silken tubes and mats often have fibres and faces incorporated into them. Check to see if any sign of surface grazing of fibres, any holes, or both on the fabrics. With fur look to see if hairs have been clipped at their base, causing loose fur and exposed hide.

You may also find them in the stored pantry products listed above.

Multiple infestation treatment options exist should you have a clothes moth infestation.  These are:

  1. Infested clothing articles or small blankets and rugs can be dry-cleaned or laundered in hot water (temperature above 49°C for 20 – 30 minutes) to kill all stage of the insects. Any items not in use should be laundered before being sealed in airtight storage containers.  This is the most common and effective method for controlling clothes moths in clothing, blankets, and other washable articles. (Because many woollen garments should not be washed in hot water, dry cleaning may be the only suitable cleaning option).
  2. Keeping fabrics clean also has the advantage of deterring the insects as they are less likely to feed on clean fabrics and prefer the heavily soiled ones.
  3. Mothball vapor at appropriate concentrations is lethal to the moths, and when possible, clothing should be stored with mothballs or flakes at the concentration recommended by the manufacturer.
    Individuals should avoid application of household insecticides to clothing or bedding, which may be poisonous to people.
  4. Freezing, heating, steaming and dry ice fumigation techniques also can be used to treat infested products.
  5. Cedarwood usually is insufficient to deter an infestation, as the oil vapor rarely reaches an effective concentration to repel or harm the insects.
  6. Strict housekeeping with attention to vacuuming carpets, baseboards, closets, and laundering all linens and furniture covers can further reduce an infestation.
  7. Clothes items can be set in the sunlight and brushed thoroughly, especially along seams and in folds and pockets. Brushing destroys eggs and exposes larvae. Larvae are strongly repelled by light and will fall from clothing when they cannot find protection.
  8. If clothes moths are detected, articles that cannot be dry cleaned, laundered, heated to temperatures over 49°C, frozen, kept in cold storage, or fumigated with dry ice can be sprayed with an insecticide. Find a product that lists clothes moths on its label and follow the directions EXACTLY Insecticides for clothes moths usually contain pyrethrins or permethrin. Pyrethrin insecticides provide quick knockdown of clothes moths, and most can be sprayed directly on fabrics if needed (in situations where fabrics cannot be laundered or dry cleaned). Pyrethrin insecticides do not leave persistent toxic residues, which makes them more suitable for clothes moth control in many cases than products containing permethrin. Insecticides with residual control, such as those containing permethrin, are best used along baseboards, margins of carpets, in closets, and in storage areas. They also may be sprayed under furniture and other areas where moths occur.
  9. Dust insecticides also can be used per the manufacturer label to treat crevices and baseboards in an active area of infestation that may otherwise be difficult to clean. Insecticides for clothes moths usually contain pyrethrins, which provide quick knockdown of clothes moths.
    PLEASE NOTE: PYRETHRINS ARE TOXIC TO FISH, BEES AND CATS (and other insects).
  10. Pheromone traps are also available to trap both the webbing clothes moth and the case making clothes moth. Place traps in closets and other clothes-storage areas. Trapping not only enables the detection of clothes moths but also provides some control, since trapped males will be unable mate.
  11. Keeping humidity levels low inside buildings creates an environment that isn’t favourable for clothes moth development.
  12. Buildings that don’t have numerous tiny cracks and crevices will also have fewer clothes moth problems.
  13. If an extensive infestation exists or larger items are infested, then a professional pest control agency should be employed for proper eradication.  We would be happy to assist you in this situation.  Please call us on 0447 847 776 to make an appointment.