What is a carpet moth?

The main species of carpet moth active in the UK is Tinea pellionella. It is otherwise known as the white-shouldered moth, case-bearing clothes moth or tapestry moth.

Less common, but with almost identical behaviours, is Trichophaga tapetzella: a carpet moth that is rarely found indoors due to its dislike of the temperatures associated with central heating, according to First Nature.

Moths go through four stages in their life cycle: egg, larvae, pupa and adult. Moth Prevention say eggs hatch in 4-10 days, with the average moth laying 40-50 eggs at a time (although sometimes up to 100 eggs). The larval stage then lasts between 2-30 months, before they mature into pupae for 8-10 days. Moths live in the adult stage for around two to three weeks. Pest control experts will generally treat the larvae, the longest stage of the life cycle. 

According to UK Moths, carpet moths have a 9-16mm wingspan. The larvae are around 10mm long and cream-coloured. In a cosy, centrally heated house, carpet moths’ life cycle can be expedited somewhat, going from egg to larvae in just six weeks according to Rentokil; add to this the facts that around 40-50 eggs are laid at a time, and that these moths thrive in out-of-sight areas…by the time you’ve spotted larvae and/or patches of moth-eaten carpet, you can have a full-blown infestation on your hands.

What attracts carpet moths?

Carpet moths have a keen sense of smell which homes in on the scent of keratin, a protein found in natural fibres such as wool, silk, fur and human hair. If living outdoors, they feed on animal fur and feathers from birds’ nests; if living indoors, they feed on woollen carpets and rugs, and the keratin-debris from animal and human inhabitants of the home also found in carpets such as: hair (human and pet), sweat, dust, food crumbs, food stains and moisture. The build-up of these things in hard-to-reach areas of carpets and rugs is a veritable paradise for carpet moths!

As a result, carpet moths thrive under heavy furniture that is rarely moved out during vacuuming and cleaning. The larvae construct a portable case around themselves, which allows them to feed from either end of the case and move it around to new areas of carpet to feed on. 

How do I know if I have a carpet moth infestation?

If you spot collections of what looks to be large grains of rice on a damaged woollen carpet or rug, it is likely that what you are looking at is a collection of carpet moth larvae or pupae, signalling an infestation. The eggs will be too small to see.

Usually, you will spot specific areas where the carpet has worn away or, more commonly, been eaten bare. Holes, where the carpet has simply been eaten through, are the most obvious indication of carpet moth activity. Rugs tend to show frayed edges and holes where moths are active.

You may also notice fine, sticky webbing on the walls or carpet/rug itself near moth infestation.

There are plentiful pictures of carpet moth larvae and damage online; if in doubt, compare what is in front of you at home with images from an internet search or consult a pest control expert.

How do I get rid of carpet moths?

As a first course of action, cleanipedia.com suggest turning your thermostat down. Moths thrive in warm, humid environments, so making your home less comfortable for them will deter activity and slow down the infestation.

Insecticides

Residual insecticides remain active for some time after application. There are many residual insecticides on the market for you to tackle a carpet moth infestation yourself. These products kill the eggs, larvae and adult moths. They generally cost between £12-17, and remain active for several weeks or months after application (depending on the specific formulation you use). You will need to vacuum up any larvae, empty the dust container or bag and double bag this in a bin bag which you then dispose of in an outdoor bin.

For insecticide sprays, ideally you want to apply as per the instructions, being particularly mindful of contraindications and ventilating the area well until it has dried.

Insecticide powders need to be applied and then left for a period of time (usually 30 minutes or so, but follow the instructions given on your product) and then vacuumed up.

With both sprays and powders, you may need to repeat the application to eradicate the moths entirely, and pay particular attention to the area of carpet around skirting boards.

Traps

Moth traps can be used to kill adult moths; these cost around £5-10.  Moth Prevention say these traps are a good way to try to limit the chances of adult moths laying eggs and therefore impede their population growth. However, you will still need to treat the pupae and eggs to deal with the infestation in a timely manner.

Natural solutions

If you want to avoid using insecticides, Cleanipedia.com suggest several natural solutions to your carpet moth infestation. Most of these work by masking the smell of keratin in natural fibres, however some also change the pH of the affected area which in turn makes it uninhabitable for moths.

Firstly, consider applying a mixture of bicarbonate of soda and white vinegar to the affected area of rug or carpet can treat the problem. Although it will not smell particularly pleasant, this method makes the surface of the fabric more acidic, an environment in which moths cannot thrive. The vinegar also has a cleaning action.

For a fresher-smelling treatment pathway, cleanipedia.com suggest filling small cloth bags with dried rosemary, thyme, mint or lavender and placing these in areas of moth activity. You will need to replenish the dried herbs every few months, as the oils they release must be fresh in order to throw moths off the scent of keratin.

According to Moth Prevention, chips or blocks of cedar wood provide a scent that will repel carpet moths. Cedar oil masks the scent of keratin, therefore deterring moth activity in surrounding fabrics. However, cedar oil is effective for around three months at best as the oils oxidize and lose their potency. So, you will need to replenish your defences with new blocks/chips of cedar wood, or sand down the blocks and apply fresh cedar oil to these periodically.

Washing and Steam Cleaning

It is wise to wash fabrics that were in the area of a carpet moth infestation, even if they are man-made fabrics. For example, sofa cushions and upholstery, blankets or throws. Moths may still try to feed on these fabrics if they are heavily soiled, causing damage, and they may also lay their eggs on them. Cleanipedia.com suggest steam cleaning affected carpets and rugs to ensure any moth eggs are killed: hiring a steam cleaner costs around £20-30 per day, depending on whether it is a weekday or weekend. If you can foresee a steam cleaner being needed in the future (for example, if you have large areas of wool carpet or rugs in your house and you want to prevent successive moth infestations) it might be worth buying one; they cost upwards of £99. 

If your infestation is large-scale, it is advisable to hire a professional pest controlled to tackle the problem.

How to prevent carpet moth infestation

The best preventative measure for carpet moths is a regular clearing regime. This needs to involve pulling out large, heavy furniture and thoroughly vacuuming the area of carpet or rug underneath, with particular care taken to vacuum the area around edges.

As well as vacuuming, build regular steam cleaning into your schedule. Cleaning your carpets regularly will ensure the detritus that attracts carpet moths- sweat, dust, hair, food stains and crumbs- doesn’t build up. Also, thoroughly clean underneath sofa cushions and wash any removable coverings.

According to Moth Prevention, as well as being useful in dealing with an infestation, cloth bags of dried lavender, cedar, rosemary and thyme act as repellents to carpet moths and so keep down any possibility of infestation.

A common way carpet moths invade a once pest-free home is when eggs or larvae lay on antique rugs or fabric furnishings which are then brought in into the home. If you buy or inherit a woollen, silk or fur rug, it is worth having it professional cleaned to ensure you are not introducing carpet moths into your home.