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  • Pest England

How do you know you have a wasps nest?

Updated: Jul 14, 2023

If you see wasps entering and leaving a hole in the ground, a wall, roof or any other part of a building between May and November then you probably have a wasp nest. You may be getting ‘unexplained’ wasps inside a room which may indicate a nest nearby. In the autumn as the days get shorter wasps get attracted to lights inside buildings which they confuse with sunrise.

Do not be tempted to block the hole up as this will make them angry and aggressive but it will not kill the nest, they will find another entrance and may even come inside the house. Some species of wasps will build outside in bushes and trees.

Wasp nests come in many shapes and sizes. Made from chewed wood and saliva which produces a papier-mâché type material they are grey or brown structures which are lightweight, durable and waterproof. After a queen has created the initial nest in the spring, the worker drones maintain and expand the nest. During peak activity in summer a nest can contain up to 10,000 wasps.

Why should a wasp nest be treated?

If you don’t treat a wasp nest it will eventually die out but before this happens the nest will produce approximately 100 fertile queens that will hibernate and start nests the following year. A nest will get larger until the autumn and it is the autumn and early winter when they are at their most aggressive and dopey. This is when they are likely to sting people. The workers have finished their job of nest maintenance and collecting food for grubs and now are feeding on rotting fruit (this makes them drunk and more aggressive). Wasp nests can stain ceilings and even eat through them in some instances.

Wasps are aggressive and will sting readily if they think the nest is in danger. Every year there are approximately four deaths from wasp stings. A wasp can sting repeatedly and when they feel threatened they release a pheromone that brings other wasps to help them. A wasp sting is very painful and even people not allergic to wasp stings, after being stung by a dozen of them repeatedly, can experience serious health issues.

Although they do some good by feeding on flies, caterpillars and other insects which damage crops, the wasp numbers are probably artificially high because buildings supply unlimited nest sites which in purely natural conditions would be restricted to caves, hollow trees and other natural cavities. They cause massive amount of damage to fruits in the autumn.

How is a wasp nest treated?

The entrance to the nest or the nest itself will be treated using a modern biodegradable insecticide that is not highly toxic to mammals, but is extremely so to wasps.

What do I need to do afterwards?

After treatment the nest will remain in a hyperactive state for up to 3-hours but usually wasp activity ceases much sooner. Keep people and pets away from the area until activity has ceased. Close windows and warn neighbours to keep away.

The 3 main points to remember are:

  1. A treated nest cannot ever be reused.

  2. A wasp nest cannot move its location, once started it is there for the duration of its life (7-8 months), nor can wasps move from one nest to another.

  3. All nests start in the spring, never later than May but the expanding populations are not often noticed until much later in the year. The population expands from 1, when the nest is started by the queen in the spring, to around 10,000 wasps in the autumn.

The nest itself is made of a substance similar to papier-mâché which will not rot or smell, so it is quite safe and hygienic to leave where it is. If the nest is accessible and you do decide to remove it, wait for at least 4-weeks as this will ensure that no one will get stung by any larvae that have hatched out after the queen has died. Occasionally scratching may be heard from the nest during this period but as long as outside activity has ceased, don’t worry as this will soon die out.

If you remove the nest immediately after treatment then the wasps that were out foraging would return, find no nest and attempt to rebuild it. When they return and find a treated nest they either get contaminated by the insecticide or exhaust themselves by flying around the nest in a state of panic.

If the nest is treated in the autumn dying wasps, queens and drones may still appear for up to 20 days after treatment. Never block the entrance to a nest unless you are quite sure the nest is dead e.g. wasps are not flying in and out of the entrance.

Pest England Guarantee

We guarantee that a treated nest will never be used again and the actual location of the treated nest will not be reused by other wasps for the remainder of the calendar year.

Wasp activity can remain for up to 2-weeks in the summer and up to 20-days in autumn after the treatment.

What products do we use?

Listed below are some of the insecticides we may use. Click to access its data sheet. All insecticides are biodegradable, almost odourless, non-tainting and do not corrode or stain, as well as being completely harmless to mammals.

How can I stop wasps being a nuisance?

Wasps are more of a nuisance in autumn as they’re more likely to sting people. This is because their nests are beginning to die off so they have no reason to be inside the nest and spend more time outside foraging for food. A particular favourite of wasps is rotten fruit which has fallen from the trees and started to ferment. This makes them drunk and they appear to be dozy, however they can be more aggressive if provoked. They tend to find their way inside buildings more often as the days get shorter because they are attracted to the lights which they confuse with sunrise.

Wasp traps can relieve, but not solve, the problem. A reusable trap will need to be filled with liquid bait and emptied regularly to remove the dead wasps.


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