Carpet beetles

The larvae of a number of beetle species can cause significant damage in wool fabrics, fur, mounted animals, hides and other products of animal origin. These involve the larvae of the common carpet beetle (Anthrenus verbasci Linnaeus), the Australian carpet beetle (Anthrenocerus australis Hope), the fur beetle (Attagenus pellio Linnaeus)

Naturally the larvae of these beetles are scavengers. They are often found in old, abandoned bird nests. In exceptional cases, vegetable substances serve as food as well. The adult insects (beetles) are often found on flowers in the summer, where they feed on pollen and honey. These insects are common in the Netherlands. Sometimes, a wandering beetle can be found by accident, which doesn’t mean that there is damage. The beetle may have looked for a place to stay during the winter for instance or accidentally have flown into the house during the spring or summer. In these cases it is not necessary to use insecticides.

The larvae of the carpet beetle have golden brown hairs in general. At the abdomen, there are several bushes of longer hairs. The shape of the larvae is somewhat stocky and the first two species reach a length of 4-5 mm. The larvae of the fur beetle are often somewhat larger and can reach a length of 12 mm. The beetles of these three species have an oval shape and are 2-3 mm long. They are dull coloured and mainly in black and brown with some lighter frayed spots or bands here or there. The fur beetle is 4-5 mm long, dark brown to black with a white spot on the pronotum and middle of the elytra.

Carpet beetles undergo a complete metamorphosis. This means that they subsequently go through the egg-larvae-pupate -imago (adult) stages. Depending on temperature and humidity, the egg stage lasts 6-35 days, the larvae stage may take 2-12 months. The pupate stage takes 5-19 days, whereas the beetle can stay alive 7-41 days after that.

Is only caused by the larvae. Considerable damage may be caused to woollen flooring, clothing and mounted animals.

Prevent bird nests under roof tiles. Seal seams and cracks.

For carpet beetle control, all hiding places where larvae are found must be treated with a residual-acting insecticide. At the sprayed locations, a residue toxic for insects is applied, which will retain its deadly effect on the insects for several months. For effective control, it is important for the resident to make all these places accessible to the exterminator of EWS. This includes plinths, seams and cracks under the edges of the flooring. In addition, it is recommended to vacuum thoroughly before the treatment, in particular in hard to reach places.

When the insects are found in a clothing cabinet or crate, one must remove the clothes so that the seams and cracks can be treated. Toys must be stowed away prior to the control measures. When treating cabinets, toys can be packed in plastic bags. After the treatment, you cant enter the house for two hours, and after that the house should be properly ventilated.

It is ill-advised to treat clothing with insecticides. Clothing and other fabric that has been affected should be cleaned (at least 30 minutes at 60°C will be fatal) and can then be repaired. In addition, insects in materials can be eliminated by storing them in a freezer for about 2 weeks (temperature lower than -10°C). A carpet beetle plague can be very resistant and it may be necessary to repeat the treatment after 8 weeks if insufficient result is obtained.

Brown house moth

The brown house moth is very common The larvae feed on vegetable and animal materials. They are sometimes found in corn lofts and in food, but cause most damage to moist wool flooring and wool fabrics.

Appearance and lifestyle
The brown house moth has a wingspan of 17 – 26 mm. The front wings are brown-black and have three black stains. The rear wings are somewhat lighter. The larvae (caterpillars) are yellow-white and can get 2 cm long. In unheated areas, there is one generation per year. The moths fly from June to August. The brown house moth is frequently found in buildings. The larvae develop in all kinds of vegetable and animal materials, such as seeds, grain, cork, linen, wool and fur. They can only develop in moist material at a high relative humidity. They are found in particular in quiet and most places, such as under rugs, under floors and in bird nests. Larvae can enter buildings via bird nests.

The damage caused can sometimes be significant. Rugs, mattress and chair stuffing, dried plants, grain products and even linen book bindings can be affected. Mainly somewhat moist wool flooring can be damaged significantly; and from there, adjacent wooden objects (plinths, furniture etc) can also be damaged.

Prevention & Control
First, the area in which the caterpillars (moth larvae) exist must be kept as dry as possible by ventilating during sunny weather or through dry-firing. In case of leakage or permanent moist circumstances, architectural measures must be taken first.

Then, control actions can be initiated, with the help of an agent based on cyfluthrin, deltamethrin of permethrin. These agents should be sprayed on the places where the larvae are found, such as under the edges of the flooring, behind plinths and in the seams and cracks of the bottom of wall furniture. Mainly when the bottom of a furniture piece is shielded by a plinth, this is where the larvae will pupate. At the sprayed locations, a toxic residue is applied, which will retain its deadly effect on the insects for several months. The aforementioned agents are permitted for the extermination of crawling insects. One should spray these agents under low pressure and with course drops. During the treatment and the 2 hours thereafter, the area should be ventilated thoroughly. Afterwards, people and pets can return to the treated area.

House borer

The beetles are brown-black and have a couple of light dots on their elytra (at the top). The females are 1-2,5 cm and the males are 8-16 mm long. The antennas (feelers) are thin and fairly long. The larvae can get about 2 cm long and are whitish.

House borers have a complete transformation, meaning that they go through 4 stages: egg, larvae, pupate and imago (beetle). Duration from egg to imago: 3-10 years, usually 4-5 years.

The house borer only affects soft wood, such as spruce, pine and fir trees in. In the months June through September, the beetles crawl from the wood via oval exits of about 4 – 7 mm. The males and the females then mate, after which the females lay eggs on the wood. The eggs produce larvae that bore into the wood 3-10 years, often 4-5 years , causing great damage. The pupation occurs and the adult beetles quickly come crawling from the wood.

Chop bore tunnels open where possible, and inject them where necessary. Replace weak would with sustainable wood Remove wood dye, paint or wax layers where possible, remove bore meal with steel brush and make the woodwork dust-free. The wood must be treated with a permitted agent twice.

Instruction for control of common furniture beetle / house borer.
For the control action:
Free woodwork from paint, wood-dye etc.
Make woodwork dust-free
Replace weak would with sustainable wood
All objects that can come into contact with the agent must be properly covered
Any loose objects that can hinder the exterminator during the control action, such as construction debris, must be removed.
In case of flooding in the crawling space / basement, resolve this before the control action.
During the control action:
The resident must leave the building with fellow-residents and pets.

After the control action:
After the control action, the treated area(s) must be properly ventilated and the resident, his fellow residents and pets cannot enter the treated area(s) for long periods of time.

Large furniture beetle

Just like the common furniture beetle (Anobium punctatum Degeer) this beetle species belongs to the Anobiidae family. The larvae preferably develop in oakwood. However, the development can also take place in other hardwood species, ans sometimes they are found in soft wood, when soft wood is processed in the immediate vicinity of affected hardwood.

The eggs are white, and have a diameter of about 0.6 mm. Because they are so small, they are hardly ever noticed. The larvae is yellowish white and can get 11 mm long. The beetle is dark brown to grey yellow and somewhat mottled. It is about 6 – 8 mm long. The beetle leaves the wood via an exit it gnaws itself. Often there are a lot of exits close together, making it look like a buckshot in the wood. The openings are round and about 2.5 – 4 mm in diameter. They are the first sign of the pest attack that can be observed.

Lifestyle and development
In April and May the beetles emerge from the wood. In heated buildings, this period can begin as early as January and proceed until June. It is assumed that some of the beetles mate in the wood after the females drop the eggs in the wood. The beetles make a loud tapping noise in and outside of the tunnels. This is what they owe their name ‘death watch beetle’ to. It was believed by some that, in a building in which this insect could be heard, someone would die soon. The development from egg to beetle lasts at least three years. The growth of the larvae depends on the presence of fungi that have settled in the wood. Mainly moist wood, which cause rot, is attacked by these insects. This can proceed to deep into the wood.

Control measures begin with reducing the moisture causes. For instance: resolving leakage, resounding walls, rising damp etc. In addition, it must be made sure that the ventilation is optimal. Under these circumstances, fungi will be unable to develop or sustain and the beetle will die after a while. However, since this can take several years, it is recommended to fight the beetle with an insecticide. Larger larvae can still survive in fairly dry wood (moisture level about 12*), although that will slow down their development.

Control of the large furniture beetle and its larvae can be done by spraying an insecticide permitted for the extermination of wood boring insects based on cyfluthrin, cypermethrin, deltamethrin or permethrin. Painted wood cannot be treated with these agents. If the wood has fungus, moisture reduction is essential. The fungi can be eliminated with fungicide based on azaconazole. Often, it is recommended to use a combined agent, that is both effective against the fungi and against the insects.

In order to use enough agent in the wood, the agents can also be injected into the wood in addition to being sprayed on the surface. Wood that still has to be processed to replace affected wood, must, preferably, haven been given a pretreatment in accordance with a professional wood preservation process with a permitted agent thereto.

For large objects and monumental buildings a hot air treatment can be considered. However, the costs thereof are significant.

Common furniture beetle


The beetles measure 2.5 mm to 5 mm in size and have a dark brown colour. They have a curved neck shield. The larvae can get about 6 mm long, are white, somewhat bent and have three pairs of legs. The eggs are white.

These insect have a complete metamorphosis, with the stages: egg, larvae, pupate, imago (adult beetle).

The common furniture beetle belongs to the dry wood borers that affect dried wood, often used in buildings. Both softwood and hardwood is affected. During the summer, the beetles exit the wood through exit openings, with a diameter of 1 – 2 mm. The males and the females then mate, after which the females lay eggs on the wood. The eggs produce larvae, that bore in the wood for about 3 years. Afterwards, the pupation phase takes place just below the wood surface. Eventually, the adult insects crawl out of the pupae, after which the cycle begins again.

The woodwork to be treated must be free from paint, wood stain etc, after which it will impregnated with a permitted substance, twice.

False blister beetle

This species is very common in our country. It looks somewhat like the longhorn beetles due to its lengthy feelers, but it is part of an entirely different group of beetles. Originally probably originating from the Great Lakes in North America, it is now present worldwide in the temperate regions.

Appearance / Lifestyle
The beetle is 6 – 12 mm long and red-brown. The ends of the elytra are black. The beetles can fly. The larvae of this beetle species can get 12 – 18 mm long and are off-white. They often live in partly decayed wood of hardwood and softwood trees. Especially piles that are half in the water can be eaten entirely. The beetles that are often found in houses and buildings in water rich areas, emerge from April to August and drop their eggs in suitable wood. Often, the breeding place must be looked for under the building, possibly in the piles or in the timber formwork that hasn’t been removed after pouring the concrete. Indoor woodwork can also be affected, however, only of the atmosphere is very humid.

Especially in Amsterdam and Rotterdam, this beetle generally occurs in houses and buildings. In certain cases, this beetle species can also live in wooden house boats. A primary life condition for the larvae is the fact that the wood has to be wet and must also have been attacked by fungi. However, it shouldn’t be rotten tot he extent that it crumbles.

In most cases, pest control is not necessary, since the beetles are likely to only attack the wood that has already deteriorated. However, an investigation into the development place is desired, to remove the affected wood (source) where possible. If wood is affected indoor, the humidity should be reduced immediately. This can be done by ventilating during sunny dry weather, or by dry firing the areas and improving the ventilation.