Common pests around the house

REMEMBER: This sheet suggests the use of certain poisons and chemicals to control the pests - these can be dangerous. Always handle with care and follow the manufacturer's instructions.


The common garden (flying) ant is black, about 3-4 mm long and usually lives in outdoor or underfloor nests.Swarms of short-lived flying ants emerge to mate in August. Although garden ants are a nuisance, they are not significant disease carriers.

Pharaoh Ants are reddish in colour and about 2 mm long. They are fairly common in flats and hotels and spread disease from drains to food. They nest within the building structure and may well be hard to get at.


Find the nest entrance and pour boiling water over the nest site. Then apply an insecticide powder. An insecticide lacquer can be applied around door thresholds or wall/floor junctions where ants run. Ant Bait work so that the ant takes the bait back to the nest, killing the whole colony after a few days; lay in along where ants run. If you have a Pharaohs infestation, you may need to contact a local pest control contractors or Environmental Health Department.


Bats sleep during the day, hanging upside down from the roof rafters or on an outside wall. Contrary to popular ideas, they do not like belfries as they like drought free locations. Various types are native to Britain and are usually seen around dusk as they sweep across the sky catching air borne insects. They cause no harm and under British law, can only be handled by licensed people.


Law protects all species of bat found in the UK as they are endangered species, it is illegal to kill or even disturb bats in their roosts. If you have a colony of bats, you should contact the Nature Conservancy Council, they will arrange for a person to visit the site and advise on the best course of action.


The adult bug is brown and about 3.5 mm long. They feed on blood, they have a needle sharp bite which pierces the skin of a sleeping human or other warm blooded animal. After it has finished feeding, the swollen bug will then crawl away to its' hiding place to digest its' meal. You may also find them under loose wallpaper or in crevices in the furniture.


Try to avoid them in the first place, good cleaning and using clean bed linen will reduce the chances of an infestation. If you have an infestation, you will need to have the premises, clothing and bedding sprayed with an insecticide spray, but this is best left to the experts - either from a local pest control contractors or Environmental Health Department.


These large, buzzing flies have shiny metallic blue bodies and are 6 - 12 mm long. They are attracted to dead meat, on which they lay their eggs as well as feeding. They are often found around refuse tips, rotting animal matter, dirt and dustbins. They spread disease between their various landing places.


Keep dustbins clean, with tight lids and away from doors and windows, Keep meat and other food covered. Use an insecticide dustbin powder. Indoors, use a vapour insecticide strip or aerosol fly-spray. You could also fit fly screens over kitchen windows.

Carpet Beetles

The Varied Carpet Beetle is 2 - 4 mm long, like a small, mottled brown, grey and cream ladybird. The larvae are small and covered in brown hair and tend to roll up when disturbed. The adult carpet beetle can fly and lives outside the house, feeding on pollen and nectar. Sometimes they lay their eggs in empty birds' nests, but they also like felt, fabric and accumulated fluff in buildings. It is the larvae that do the damage, which usually consists of well-defined round holes along fabric seams.


Check the loft and eaves for old birds' nests or dead birds and remove them. Keep fluff and debris under control within the house, including the airing cupboards, shelves, floorboards, carpets and upholstery. Vacuum carpets on a regular basis. Lift carpets and underlay and clean floors and carpet thoroughly. An insecticide is needed to deal with a bad carpet beetles infestation and affected items can be sprayed or dusted.


Distinguished by their very long, whip-like antennae, flat oval bodies and rapid jerky movements. The adult German cockroach is brown and about 12 mm long, the Common or Oriental cockroach is about 20 mm long. They eat all kinds of food - meat, vegetables, fruit, bread, even paper and leather. Cockroaches thrive around heating ducts and boiler rooms of large centrally heated buildings and cluster around pipes, stoves and sinks, especially in humid areas. They taint food with an obnoxious smell and may be carriers of various diseases, including serious food poisoning.


Control is seldom easy because it is difficult to get the insecticide to the insect. The insecticide should have sufficient persistence to kill baby cockroaches as they hatch. If this fails call in your Environmental Health Department or pest control contractor.

Death Watch Beetle

A wood boring beetle, the grubs eat old hardwood. Adults rarely fly, so infestations are generally restricted to areas where previous infestations have not been completely eradicated or where old, infected timber has been introduced. They prefer hardwood, not the softwoods used in modern softwood house timbers. Grubs live up to ten years inside timber, emerging as adult (mottled grey/brown) beetles about 7 mm long. They produce a rapid tapping sound by beating their heads against the wood as a mating call.


Persistent and thorough use of a proprietary woodworm killer will deal with small outbreaks. Call in a wood preservation company for large infestations.


Earwigs are easily recognisable by the pair of pinchers at the end of their abdomen. They are dark reddish-brown, with light brown legs, about 15 mm long. They are primarily nocturnal, with some species being attracted to lights. They are considered scavengers, eating almost anything, but some are predatory. They also eat live plants.

They can be found in the homes, but prefer cracks and crevices. Their populations will build up around foundations. They can produce large populations rather quickly. Earwigs can live in habitats that also house other insects. Their habitats are environments like mulch, pine straw, leaf litter, etc.


The removal of their habitats is very important for controlling earwigs .

Vapour strips can be hung around all entry points, windows, doors, plumbing under sinks, skirting boards etc. Spray can be used in uninhabited areas such as garages and basements. In addition, spray the area around the outside of the house. Alternatively baits are available which can be laid down in the general area of infestation.


Their little 2 mm bodies are flattened from side to side and they are well known for their ability to jump. The tiny white eggs are laid in small batches on fur, hair, feathers or the sleeping places of the host (human, animal or bird). Adult fleas feed on blood and their bites can cause intense irritation. The cat flea is the most common and readily bites humans. August and September is when they are at their peak.


Treat any infested pets with a special veterinary aerosol, powder or shampoo - injections are now available from vets to protect pets for a period of time. Burn infested bedding and spray or dust a suitable insecticide into all cracks and crevices in walls and floors. Remove old birds' nests etc. from around the house.


Around 10 mm long, the House Fly is the most common pest in buildings and is found in most homes. They feed by vomiting saliva on to the food surface, treading it in and sucking up the resulting liquid! The fly is a health hazard; it passes on dangerous germs from the last place that it visited - which could have been anywhere from a dustbin to animal droppings!


Scrupulous hygiene and prompt disposal of all rubbish will discourage flies. Keep food covered and site dustbins away from doors and windows. You can also fit fly screens to doors and windows.. There are a number of fly-killer aerosols on the market as well as impregnated plastic strips giving off insecticide vapour.


Mice are usually detected from their dark coloured droppings as well as noticing damage to stored food, packaging or woodwork. Mice have a compulsive need to gnaw; electric cables, water and gas pipes, packaging and woodwork can all be seriously damaged. They climb well and can squeeze through very small gaps. They contaminate food and can carry many diseases, particularly food poisoning.

If you live in or near the country and think you have mice, you may have field-mice or other furry creatures; they cause just as much damage but tend to be less dangerous.


Keep your home mouse-proof, this means blocking all possible routes into the house. While they can get into a cavity wall or roof space, they will be very hard to eliminate - check that the structure around all pipes projecting through the outer skin of the house are fully sealed. Proprietary mouse killers are available for household use and more powerful methods are available but can only be used by pest control contractors or environmental health departments.

There are humane mouse traps available. They usually consist of a box that the mouse is tempted into. Once trapped you simply let the mouse free into an open area a long way from your home.


The clothes moths have infested many households. Two kinds are common:
  • The case-making moth is so called because the caterpillar spins a shelter case of silk and bits of the material on which it is feeding.
  • The webbing clothes moth, the most abundant and injurious species, spins silky webs as it moves over a piece of material.

The adult moths are probably harmless. The clothes moth stays in dark places and flies very little. However the female begins to lay eggs, before it is a day old, and lays about 100 in the 7 to 14 days of its life. The soft, white eggs are laid loosely upon the material on which the larvae are to feed. They are easily dislodged and crushed, so thatanything that is regularly brushed or shaken should not become moth infested. In warm weather the eggs hatch in from four to eight days. In colder weather, hatching may take as long as three weeks. The larvae eat furiously for about 40 days before turning into pupae. The pupa stage lasts eight to ten days in warm weather, and three to four weeks in the winter in a heated building. Eggs, larvae, and pupae die quickly at low temperatures.

It is the larvae that does the damage to clothes and are about 12 mm long white worms. Adults are yellow-brown, with narrow wings, about 12 mm long. They eat protein based material, they have an unusual ability to digest keratin. Keratin is found in woolens, furs, hair, leathers, hides, feathers, horns and stored meat and dairy products. Clothes moths hardly ever damage synthetic materials. Keratin is also found in hair, skin and nail tissues. Clothes moths will damage silk and linens, and synthetics, but it will be incidental, while the larvae are eating their preferred foods. They particularly damage fabrics stained from oil from human hair, human sweat, urine, beer, milk, soft drinks and juices.


The first order of business is to clean stored clothes. It is important to identify the source of infestation. Besides looking where clothes are stored, look around your baseboards for fluff. At times they can be found in your kitchen and in bird nests. Vacuum very well all the cracks and crevices of the infested area and spray with a suitable aerosol and place a cloth moth trap. The old fashion moth balls (with their distinctive smell) can also be used when storing clothes.


The Common, or Brown Rat is about 250 mm long and is a creature of habit, living both above and below ground. The Black Rat (the original plague carrier) is smaller - about 175 mm long and is an agile climber. They breed rapidly and, like mice, need to gnaw constantly. Brown Rats burrow underground or into soft material; refuse tips, loose soil under sheds and straw are likely sites. They damage woodwork, plastic and pipes and will sometimes strip insulation from electric cables by their gnawing (until they met their maker in a flash!). They spread many diseases including food poisoning. They contaminate more food than they consume and their urine can pollute stagnant water.


Block off gaps under sheds and move loose piles of wood. Do not encourage rats by leaving scraps of food out of doors, if you think you have an infestation, stop feeding the birds as you could be feeding the rats. Poison is available as proprietary, ready-mixed bait. Serious or persistent infestations should be dealt with by a pest control contractors or Environmental Health Department.


(if you call him a pest !)

House spider help us by eating a large number of household pests. None of the native British types are poisonous to man. The reason why they are often found in baths and sinks is that they cannot climb smooth surfaces, so if they fall in, they are stranded.


To remove a spider there is no need to kill it. Simply place a carton over it, then slip a piece of thin cardboard between the carton and the surface to form a lid. Then take the sealed container out of the building and let the spider go.


Around 10-20 mm long. The queen wasp is larger and hibernates over winter, making a new nest in the spring in which she lays her eggs. If annoyed or threatened, wasps will sting. They can come into the house where they are attracted to sweet things (jams, fruit etc.).


You can fit screens over windows if wasps are a major problem. Individual wasps can be killed with a fly-killer aerosol. The old-fashioned method of filling ajar one-third full with jam and water, covered by a punctured paper lid will drown them. If you find a wasps nest in a wall or bank, and are brave, apply a powder insecticide product from a puffer pack labeled for wasp nest control. Thoroughly spray nests in roofs or sheds with an insecticide. This can be dangerous as the wasps can become angry and attack any animal (including humans) in the area and is best performed by professionals. Some local councils will do it for free.


Typically 12 mm long, with oval, grey segmented bodies and 14 legs with prominent antennae. Woodlice are quite harmless although may damage plants indoor and out.


Not necessary to remove them unless they persist. Put right any dampness, remove infested vegetation and use an insecticide powder or long- lasting spray around door thresholds.


This is a term used for the destructive larvae of several species of wood boring beetle. The first sign of woodworm is the appearance of neat round holes 1-2 mm across in wooden surfaces, often accompanied by tiny piles of wood dust. The adult Furniture Beetle is a small brown insect about 5 mm long who can fly and lay eggs on rough, unpolished wood. The grubs bore straight into the wood - leaving no trace until they emerge as beetles three or more years later, usually between May and September. They are usually introduced into the house in second-hand furniture, tea-chests and the like but they can also fly in through windows from nearby dead branches of trees. They may attack floorboards, joinery and, more seriously, structural timbers.


In furniture, woodworm can be cured by application of a woodworm killer which will penetrates quickly and can be applied using a brush or spray. As the pest is inside the wood, the liquid should be applied quite generously. You can also buy an insecticide polish as a precaution against woodworm. You can buy proprietary fluid used by the experts and treat woodworm in structural timbers yourself. All timbers should be cleaned first and any roof insulation material will have to be removed temporarily so that you can get at the joists. Cover electric cables and the cold water storage tank. Lift floorboards to get at the undersides and joists. You can have detailed surveys, reports and estimates carried out by specialist wood preservation companies and many cover their treatments by long term guarantees - this may help if you sell the house so it is worth considering the additional initial cost for a subsequent benefit.

REMEMBER: This sheet suggests the use of certain poisons and chemicals to control the pests - these can be dangerous. Always handle with care and follow the manufacturer's instructions.