Wasps

Top

Last revised: 22 November 2007

wasp

Description

The most common wasps are the German Wasp and Common Wasp. Their bodies have a characteristic black and yellow band across the abdomen. They are fairly large insects approx. 30mm in length

Distribution

Both species of wasps are commonly found throughout Britain and Northern Europe, and they are social insects forming colonies inside their nests.

Life cycle

In the spring, the queen leaves her hibernation site and seeks a suitable place to build her nest. She constructs a golf ball size construction from wood pulp and then a small number of eggs are laid and tended by the queen until they hatch to produce the larvae, which she also feeds and tends.

When fully grown the larvae pupate and sterile female workers emerge. These take over the job of enlarging the nest and foraging for food and insects for subsequent eggs laid by the queen.

Wasp’s nests may be found in roof spaces, wall cavities and air grates of buildings, hanging from trees, as well as underground. A normal wasps nest can contain from 3,000 to 5,000 individuals depending on it’s size, by late summer.

Towards the end of summer fertile males and young queens emerge from the nest to mate. The young queens will then fly away and select a suitable site to hibernate over the winter.

In the late summer before the onset of the colder weather the remaining males and worker wasps will forage for sugary foods such as jam, fruit etc. They will also feed on ripe and fallen fruit and become tipsy in the process. This is when they tend to become aggressive to anyone interfering with them.

As the weather becomes colder the active nest dies out, but the new Queens born during the summer will search for a hibernation site. In the spring they will start a new nest of their own, the old nests are not re-colonised by the new queens.

Significance

Wasps feed on other insects i.e. flies and spiders and can be beneficial to the environment. Where wasps nests are situated away from occupied areas and are not causing a nuisance, they may not need to be treated.

Control Methods

Knockdown insecticidal aerosol spray i.e. ‘Flying Insect Killer’ can be used to treat occasional wasps that become a problem when they appear indoors. Only a product suitable for use indoors should be used.

Wasps nests that are not causing a problem can be left alone. You can dispose of any old nests at the end of the following year. You may encounter queens that have chosen to hibernate in the nest for the winter period if you move it too soon. Old nests will not cause any damage if left in place.

For nests at ground level an insecticidal dust can be applied around the entrance of the nest.

Nests that are built in lofts or under eaves are more difficult to treat yourself and are best treated from the outside. If the nest is treated from inside the loft you may not be able to get at the nest entrance to treat it effectively and if you disturb the nest during treatment you may encounter a swarm of angry wasps trying to protect their nest. Care must be exercised when treating wasps nests and the best time to attempt treatment yourself with products sold by hardware stores is at dusk when the wasps are less active.

The Council does offer a service to treat accessible wasp’s nests, further information on charges can be found on the Council website or follow this link. Wasps (Please note the nest is not removed after treatment, as old nests are not re-colonised)

Independent pest control companies also offer professional treatment of wasps nests and their details can be found in local telephone directories and Yellow Pages.