Carpet Beetles

What are Carpet Beetles and how to get rid of them

Carpet Beetles can be a real nuisance in the home. Their larvae (known as 'wooly bears' cause damage by chewing holes in various household items such as carpet, furniture, bedding, manchester, clothing and accessories. In some people, contact with the fine hairs from cast skins (moults), or, from living and dead beetles and larvae, can cause an allergic or skin reactions such as dermatitis. Given the unnecessary destruction of property and the potential health risks associated with Carpet Beetles, it’s important to prevent and control infestations in the home.

Description

Adults are beetles, while their larvae are grub-like and covered in bristly hairs.

Adults are generally 4 mm long and are a compact oval shape. Some species, such as the more common introduced European Carpet Beetle (Anthrenus verbasci) have a mottled banding pattern of pale-brown or yellow, brown and white scales, while other species are plainer and blacker.

At the front of the small head are two compound eyes and a short pair of club-like outward facing antennae. On the underside of the head are chewing mouthparts.

Behind the head is the first segment (pronotum) of the middle section of the body (thorax). In beetles, this segment is quite pronounced and is a round-shaped plate with a point directed towards the rear. Behind the pronotum, attached to the upper side of the body, are two pairs of wings. While at rest, the hardened front pair provides protection to the semi-transparent flying pair. On the underside and middle section of the body are three pairs of thin outward facing legs.

Larvae are up to 5 mm long, are light brown to yellow in colour and have a large head which tapers to a smaller rear (abdomen). Larvae have a distinct head capsule with chewing mouthparts and three pairs of legs towards the front and underside of the body. Larvae are covered in thick bristle-like hairs, often in transverse bands along the body, with dense tufts at the tip of their abdomen.

Behaviour

When disturbed, beetles fold and hide their legs close to their body, while larvae erect their bristle-like hairs in defence. Adults are attracted to light, while larvae prefer dark and sheltered places.

Lifecycle

After mating, females fly to a suitable laying site where future larvae can feed on a food source. Females lay up to 40 sticky eggs which are laid individually at various locations. Eggs are less than 1 mm in length, oval-shaped and cream-coloured. Eggs generally hatch within 10 to 20 days.  

Larvae are grub-like and shed skin (moult) at each stage of growth development. During cold periods, larvae can hibernate until warmer weather returns. In spring, larvae find a sheltered and dark place to pupate, often burrowing into their food source. Larvae pupate in their final skin and emerge after 10 to 30 days as the adult beetle form. Depending on the species, larvae can live from 1 to 3 years, while adults generally live and die within 2 to 6 weeks. 

Habitat

Adult Carpet beetles are predominantly found outdoors and feed on the pollen and nectar of flowers during the day. During breeding season, females sometimes venture indoors to lay eggs.

Depending on where Carpet Beetle eggs are laid, larvae can be found either indoors or outdoors and are most active during the night.

Larvae can be found indoors feeding on natural fibres including animal fibres such as silk, leather, feathers, wool and hair; and plant fibres such as cotton and other foodstuffs. Larvae also feed on the skin and hair of dead animals and insects; and spiders’ webs.

Larvae are often found in crevices, junctions and seams of household fabric items such as:

• Carpet
• Wool insulation
• Furniture
• Bedding and manchester
• Curtains
• Clothing and accessories
• Natural fibre hair brushes
• Wigs
• Musical instruments, especially the pads in woodwind instruments and felt found in pianos
• Taxidermied animal skins
• Entomology collections

Larvae can be found outdoors in:

• Animal houses such as chicken coups and dog kennels
• Bird and mammal nests
• Bee hives and wasp nests
• Near dead animal carcasses

Natural enemies

Birds, mammals, lizards, frogs, ants, spiders and parasitoid wasp larvae feed on Carpet Beetle larvae.

Best treatment for Carpet Beetles

Spray carpets, skirting boards, under furniture and around entrance-ways with Blitzem! IndoorOutdoor Barrier Spray Ready to Use.

To reduce the potential for dermatitis reactions to the cast skins, or from living and dead beetles and larvae, wear gloves and use a dust pan and broom to pick up mess.  Ensure areas are well vacuumed and wipe hard surfaces with a moist paper towel, then discard into the rubbish bin.

Wash any garments and linen suspected to be infested with eggs in the washing machine in hot water and then place into the dryer for at least 30 minutes.

Symptoms of Carpet Beetle damage

Carpet Beetle larvae damage can cause holes in carpet and other fabric household items. However, damage can be confused with that of Silverfish and Clothes Moths.

Further evidence of Carpet Beetles in the home:

• Adults - often found on window sills or in window frames, where they are attracted to the light
• Living or pupating larvae - generally found on or in a food source
• Cast skins of larvae
• Fine hairs from the larvae
• Faeces - small, black and grain-like in appearance

How to prevent Carpet Beetles appearing

Prevent Carpet Beetles from entering the home:

• Reduce entry points to a building: repair holes, cracks and gaps in walls, skirting boards, windows and doors.
• Ensure flyscreens are fitted and maintained. If possible, cover vents with a fine mesh.
• Install a door seal or door snake to the bottom of entrance doors
• Check floral arrangements for adult Carpet Beetles prior to entering the home.
• Avoid purchasing second-hand furniture, otherwise thoroughly inspect furniture for signs of Carpet Beetle eggs and larvae prior to bringing into the home.
• Check fabric items, especially after washing and hanging on the line, prior to bringing them back into the home.
• Avoid using outdoor lighting, as bright lights tend to attract Carpet Beetles and various other pests into the garden and home.

Remove potential food sources:

• Keep human and pet food in sealed containers. 
• Ensure any dead rodents, spiders, insects and other animals are collected and disposed of quickly.
• Remove any bird, rodent or wasp nests and spider webs from in and around the home.
• Where possible, keep products or items made of natural plant or animal fibres in plastic sealed containers. For unused fabric items, use vacuum sealed bags.
• Periodically wash then dry unutilised fabric items.
• Avoid returning stained or dirty fabric items to cupboards.
• Ensure house is hygienically maintained, focusing on areas where dust, hair and lint accumulates, especially underneath and behind furniture.

Monitor and control quickly:

• Check for Carpet Beetle adults and larvae regularly in areas such as in the roof void, ventilation duct, cupboards, linen press, lighting fixtures and along skirting boards. Also check in the crevices, junctions and seams of fabric items, as Carpet Beetle larvae are known to dwell in them and consume.
• Treat at the earliest sign of infestation when populations are smaller and much easier to control.