The wasp is a common problem throughout summer in the UK and other parts of Northern Europe. They are social insects that form colonies inside nests. Nests are often found in soil banks, roof spaces, and in areas within trees and walls.

Biology

The queen wasp will emerge from its hibernation around mid-April time and will search for a suitable site for her colony. The queen wasp will then build the foundations of the nest by using chewed bark and dried timber mixed with saliva. The nest at this point is no bigger than a golf ball in size and within this nest she lays between 10 and 20 eggs. The first brood of adult workers takes over the tasks of enlarging the nest and providing food for subsequent eggs laid down by the queen. By the end of the summer, the nest can contain between 3000 and 5000 wasps and measure over 30 cm across.

Later in the summer, males and young queens emerge and mating occurs. Once fertilised, the queen flies away to find a suitable site for the winter. Once the cooler weather comes, the workers and remaining males become lethargic, and they feed off ripe and over-ripe fruits. This can produce aggressive behaviour to anyone interfering with them.

The onset of the cold weather kills off all of these workers and males, and it is only the queen that survives in hibernation to start a new colony in the spring.

Importance

Wasps do visit bins, waste depots and dead animal bodies and therefore they have the possibility of spreading diseases, but they are mainly known for their nuisance in the late summer.

In the early parts of summer, wasps are too busy collecting food for the nest, however later in the season as the larval rearing decreases, the workers and males turn to sweeter products and they become nuisances in homes, bakeries, offices etc. They also have the ability to sting apparent threats, a habit which increases as the insect becomes more irritable with the onset of the cooler weather, and the feeding on fermented, over-ripe fruits.

Control

Some people are allergic to wasp stings, but nonetheless, it still becomes an irritant if you're not. Wasps are generally easy to control if access to the nest can be achieved. Control of adults in flight alone will unlikely to exert much control over an active nest, however strategic positioned wasp traps, such as Waspbane, will attract nuisance wasps away from sensitive areas for example children play-areas or public parks and gardens.

The main aim should be to disable the nest by applying a residual insecticide to the nest entrance. If the nest in found in a loft space, shed or anywhere indoors, the use of mini-smoke generators is beneficial to knock down the majority of the worker wasps. Wasps re-entering the nests will need to come into contact with the residual dust, and they will naturally walk to product into the nest, thus killing it off.

Nests are often found in loft spaces, cavity walls, behind cladding, in flower beds etc. Be careful when treating wasps in loft space etc. and make sure there are no signs of bat activity.

In general residual dusts are far better then residual sprays. Most residual dusts are ideal, for example, bendiocarb and pyrethriod.