Guide Other pests

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2. Black ants

Overview

Black ants are commonly found throughout the UK and although they nest outdoors, they can sometimes be found inside buildings causing a nuisance. You can find nests in dry earth around plant roots and the sand used in house foundations, garden paths and patios. Ants are social creatures and live in colonies containing workers (infertile females), males, queens and grubs (larvae). Ants mate on the wing, so the 'flying ants' are either males or immature queens. Worker ants are very active foraging on a wide range of food including sweet substances, seeds, insects and aphid secretions (honey dew). Nests may survive for many years but young queens leaving the nest as ‘flying ants’ start new ones each year.

Importance

Although it is unpleasant and a nuisance to find a large number of ants entering your home, they don't transmit any serious disease. However, ants may have travelled through unpleasant or dirty places during their foraging beforehand which taint any food which they come in contact with and make it unsuitable to eat.

How do I get rid of them?

Treatment is only really necessary when ants become a serious nuisance within a building. We have included some guidance below:

  • The most effective method of control is to find and destroy the nest. Look outside next to exterior walls of the house and under paths or slabs and check for small piles of earth or watch for ants moving back and forth from nest to food.
  • Once the nest has been located, pour boiling water over the nest which should destroy a large number of ants in and around that area. This should be followed-up by puffing an insecticidal powder product into the hole. Select a powder product which lists ants on its label.
  • There are other insecticidal products which can be used in and around entry points into the home and applied to cracks around door and window frames, airbricks, behind kitchen units and around waste pipes.
  • Other products on the market cause the workers to destroy their own nest and include a sugar based liquid bait which contains an insecticide; the workers are attracted to the bait and take it back to the nest for the larvae and queen to feed on.
  • There are different treatments for ants, including powders, gel baits and sprays all of which can be purchased from local hardware stores or garden centres. It is important to read all manufacturers guidance carefully when using insecticides.  
  • As far as possible, seal any entry points where ants are gaining access into the property.
  • All sweet foods should be kept in containers with tight fitting lids, crumbs swept up and as little food waste as possible left lying about.