Garden ants

Garden ant

One of the commonest insects that invades houses is the garden ant. The ant is an active insect and nests outside, in grass, walls and under paving.

It enters buildings in search of food. The garden ant is a relatively large ant 3-5mm in length and dark brown to black in colour.

Life cycle

The garden ants mate in flight when winged males and females swarm between mid July and mid September.

After mating the male dies and the female loses her wings and buries herself in the soil over winter. In late spring the female lays eggs which hatch into white larvae in 3 - 4 weeks.

The larvae are fed by the queen and when fully grown pupate. The worker ants which emerge from the pupae feed new larvae and the queen.

The life cycle is complete within 2 months and in favourable conditions the nest can last for years. 

How can ant infestations be controlled?

The nests of ants can be located by following their trails, and by observing small piles of fine earth brought up for example from under paving stones.

  1. Boiling water poured on the nest will control the infestation for a short time at least.

  2. Followed by puffing a residual insecticidal powder product into the hole. Select a powder product which lists ants on its label.

  3. Ensure that sugary foods are kept in sealed containers and all food spillages are cleared up.

  4. Flying ants should be controlled by using an appropriate insecticidal aerosol for flying insects.

  5. A residual insecticidal laquer can be applied around door thresholds, wall/floor junctions, windows, ventilators, ducts and drains, in fact anywhere you can see ants run. Attention should be given to small cracks.

  6. Some products cause the workers to destroy their own nests. For example sugar based liquid bait containing borax. The workers are attracted to the bait and carry the insecticide back to the nest.

Will the treatment affect animals?

Some products on the market are harmful to pets, others are not. It is important that you read the label and follow the instructions taking all the necessary precautions when applying the product.

Date of last review: 28 August 2015