A helpful overview of the two pests commonly encountered in wardrobes: the case-making clothes moth and the webbing clothes moth.
Holes in clothing or eaten areas of carpet could be caused by a number of pests including carpet beetles, silverfish and even cockroaches. However, clothes moths are perhaps the most common cause of damage to clothing and certainly homeowners will often jump to that conclusion when finding a hole in their favourite piece of clothing.
The challenge with a potential clothes moth problem is firstly confirming that clothes moths are indeed the problem; secondly, finding the source of the infestation; and lastly, carrying out a comprehensive treatment such that the problem doesn’t resurface. This is certainly an area where the expertise of a pest manager can help.
Clothes moths are a year-round problem. Although they are slowed down by cooler temperatures, the colder areas of Australia have indoor heating, thus allowing clothes moths to breed continually. That said, their life cycle will take longer at lower temperatures. Larvae can undergo 4-45 instars (!) over a period of between one month and two years before pupating into an adult. There is generally a peak in emergence in spring and a smaller peak in emergence in autumn.
Species Snapshot – Clothes Moth
Latin names: Tineola bisselliella and Tinea pellionella.
Common name(s): Tineola bisselliella – webbing clothes moth or common clothes moth. Tinea pellionella – case-making clothes moth or bagworm moth.
Webbing clothes moth description:
Larva: Pale caterpillar with dark head, feeds in folds of fabric and creates patches of webbing that get covered in droppings.
Adult: Small moth up to 7 mm long. Pale beige, slightly shiny forewings that are folded over the grey rear wing when at rest.
Case-making clothes moth description:
Larva: Pale caterpillar with dark head, moves around inside a tubular case made from silk and fibres from surrounding clothes.
Adult: Small moth up to 7 mm long. Silvery grey/brown, sometimes with faint dark-coloured spots.
Native distribution: Western Eurasia, now widespread globally.
Local distribution: Australia wide.
Fabrics attacked: Feed on animal fibres such as wool, fur, silk, feathers and leather.
Damage: Irregular holes in clothing. The size of the hole increases with time. Can create bare areas in woollen carpets.
Peak season: Active year round. Increased activity around Oct/Nov.
What do clothes moths eat?
It’s the larvae that cause all the damage, eating a range of animal fibres – especially wool, fur, silk, feathers and leather – to access the protein, keratin. Synthetic fibres or cotton fabrics are rarely attacked by clothes moths unless blended with wool or soiled with bodily fluids. The larvae don’t eat quickly, but if they are left alone or are present in large numbers, they can cause a large amount of damage. However, even one hole in a favourite piece of clothing can be an expensive disaster. The adult moths do not eat, are poor fliers and will often only be seen when clothing is disturbed.
“How did clothes moths get into my house?”
Given the adult moths are poor fliers, it begs the question as to how clothes moths get into a house in the first place? Although it is possible they may have flown in from a neighbouring property, especially in a unit block, it is more likely that they have been brought into the home unintentionally on an older piece of clothing, blanket or rug, possibly from a charity shop. Eggs on the clothing of visitors is another possibility. However, it is important to remember that in their natural environment, clothes moths are associated with nesting areas of bird and mammals, feeding on their nesting materials and carcasses. As such, if a house has a clothes moth problem, it will certainly pay to have a look around for bird nests, rodents and possums, as the potential source of infestation. Don’t ignore wool insulation in the roof void!
Webbing clothes moth vs case-making clothes moth
There are two types of clothes moth: the webbing or common clothes moth, Tineola bisselliella (main picture, right) and the case-making clothes moth (main picture, left), of which there are several species, the most common being Tinea pellionella. They are both small moths, up to 7 mm long. The webbing clothes moth is a uniform light beige colour and the case-making moth a brown/grey colour, but often with darker spots.
Both moths have a very similar habit of preferring to lay eggs and hide in undisturbed, low light areas, such as within rugs, edges of carpets, under furniture and within rarely used clothing. As their names suggest, the larvae can be distinguished by how they protect themselves whilst feeding. The case-making clothes moth builds a silken tube in which it hides as it crawls across the fabric. The webbing clothes moth builds a silk shelter that it hides beneath as it feeds. Both structures become coated in fibres from the associated fabric and droppings, making the larvae very hard to spot.
How to get rid of a clothes moth problem?
A thorough inspection is required before any treatment to determine all infested areas and whether there is a potential source from animal nests in the roof void or subfloor. All wardrobes and clothes drawers need to be emptied of clothing and all items inspected. While it is tempting only to deal with obviously infested clothes and treat the areas in which those clothes were stored, with larvae and especially eggs very difficult to spot, it is best practice to assume that all clothes are infested. Rolling the dice and carrying out only a partial clothes inspection or treating only the obviously infested areas runs the significant risk of the dreaded callback.
Freezing for 1-2 weeks or exposing the clothes to heat, greater than 50°C for at least 30 minutes, will kill any eggs or larvae in the clothes. The appropriate strategy depends on the fabric and how sensitive it is to heat. For those fabrics able to handle a heat treatment, a number of options are available: hot wash cycle, dry cleaning, heating using a hair dryer, placing in an oven and putting clothes in a sealed plastic bag in the sun for a few hours (note that it can take a while for the centre of the bag to get up to temperature).
It is then necessary to treat any infested or suspected areas of activity with an insecticide spray. Using a suitably labelled product, spray the inside of drawers and wardrobes, the edges of carpets, rugs and under furniture – this should form the mainstay of the treatment.
How to prevent a clothes moth problem?
Homeowners can take three key actions to prevent a clothes moth problem from occurring:
- Make sure clothes to be packed away at the end of each season are placed in a sealed bag or suitcase
- Vacuum all carpeted areas thoroughly, including under furniture
- Check any incoming second-hand fabrics and wash/ freeze/heat as appropriate.
Are clothes moth infestations becoming an increasing problem?
Some anecdotal evidence suggests that clothes moth problems may be increasing. A warmer winter speeds up the life cycle, a move to lower temperature/eco wash cycles means eggs are not killed in the wash, there has been a shift back to using more natural fabrics in fashion, and wool is being increasingly used as insulation, providing more potential food sources for clothes moths. In the UK, traps used at English Heritage properties showed a 216% increase in clothes moth catches between 2012 and 2016.
With homeowners often trying (and failing) to tackle clothes moth infestations themselves, it pays for pest managers to know how to carry out a successful clothes moth treatment, as homeowners are typically frustrated, often having suffered some costly damage before giving their local pest manager a call.
More information on clothes moths and other fabric pests.