Pest Control - Ants

The Black Ant (Garden) - Lasius Niger

Black ants are common in all parts of the UK. They usually nest outdoors favouring sandy or dry soils near house foundations and under paths. They are also increasingly found in cavity walls of properties.

Worker ants invade buildings foraging for food, particularly of a sweet nature. They enter buildings through tiny crevices under kitchen units, skirting boards or anywhere there is a gap big enough for an ant. When an ant finds a food source other ants will soon join them, sometimes in large quantities.

Once established and due to the location of the nest, a colony can be difficult to eradicate 100%. Nests in most cases are impossible to locate.

During late summer flying male and queen ants can be seen swarming (flying ants). Ants mate on the wing and can swarm for a few hours. They are a nuisance for a short time and can be dealt with immediately, using a suitable flying insect spray. They can also be vacuumed up, if occurring indoors.

Control

If the nest can be located it can be destroyed using ant powder or ant spray. If the nest cannot be found (most cases) then you can use various treatments. There are powders, sprays and gels available at most garden centres and DIY stores. The powders should be used outdoors around your property in cracks and crevices, airbricks and other entry points to create a barrier to exclude ants.

Water based sprays can be used inside your home e.g. kitchens, fireplaces or wherever you see ants. Spray all around the edges of a room and leave to dry. Continuous treatment may be needed for a few weeks to eliminate ants. Ant colonies will not be eliminated overnight. Ants will still be seen after treatment, as the ants must walk across the sprayed area to kill them.

Ant gels & liquids are also available, these are poisons with a sweet base to trick the ant into feeding & carry the bait back to the nest. However treatment must be continuous for several weeks and ant sprays & powders should not be used with these products or you will simply kill the ant before the ant gets to the nest.

Remember Ants do not bite, do not carry diseases, and are not a public health hazard.

Oxford City Council's Pest Control team can treat Garden Ants for you. Please call us on 01865 249811 to find out how much it will cost and when we can visit.

Pharaoh's Ant - Monomorium pharaonis

Pharaoh's ants originated in the North Africa/Mediterranean region, spread along international trade routes and are now widely distributed. Their need for warm humid conditions means that in temperate lands they are confined to buildings. Infestations can he found in a wide variety of locations including residential blocks, hotels, hospitals and other institutions, food handling premises, zoos and on board ship. In warm climates infestations can be found outside.

The insects may be associated with the fabric of buildings (e.g. wall voids, windows, storage areas etc), plants and sterile supplies. Infestations spread through buildings by way of service ducts (e.g. heating and electrical conduits). The ants will forage for water around sinks and where condensation has occurred (e.g. windows, walls etc).

The ants can survive low temperatures for prolonged periods with the workers continuing to forage for food. The minimum temperature for success is 18ºC and the colonies thrive at 30°C. Infestations in buildings are relatively unaffected by the seasons although may be encouraged when heating systems are switched on during the winter.

Life Cycle

Pharaoh's ants are social insects and live in colonies. These range in size from a few dozen to 300,000 ants. Colonies consist of: workers (sterile females), fertile males and queens (fertile females). There are usually many queens in a colony (multi-queen colonies) and they co-exist amicably. The queens can he replaced so colonies will survive indefinitely. New colonies are typically formed by budding and may he encouraged by disturbing nests. Adult ants are responsible for this process which may include queens. Worker ants carry larval stages to anew nest site from which they can rear queens and males. Temporary nests may he established whilst the workers search for new sites. If established in mobile equipment infestations can he widely distributed.

The workers provide food for the colony and maintain the nest. Only 5-10% of workers are actually engaged in foraging. Fertile males and females develop from well fed larvae. Flying swarms are never seen, mating taking place in the nests and interstices of buildings.

Each queen produces up to 350 eggs. These hatch in about a week to give legless larvae which are fed by the queens and tended by the workers. Larval development takes approximately three weeks. The pupal stage lasts about nine days. The whole cycle from egg laying to adult takes about 5½ weeks depending upon temperature.

Control

Successful control of Pharaoh's ants requires the destruction of nests. This is difficult to achieve because nests are often located in inaccessible places. You should seek professional help to control Pharaoh's ants.

Oxford City Council's Pest Control team can treat Pharaoh's Ants for you. Please call us on 01865 249811 to find out how much it will cost and when we can visit.