Common waspVespula vulgaris — identification, signs & control

• Workers 12–17 mm, queens up to 20 mm, with bright yellow and black bands on the abdomen.
• Smooth, shiny body with very little hair and a sharply pinched waist.
• A black anchor-shaped mark on the yellow face; the similar German wasp usually shows one to three black dots instead.
• Wings fold lengthways along the body at rest, so they look narrow.
• Yellow legs and long black antennae.
• The nest is chewed wood pulp, grey-beige with a scalloped, shell-like pattern and a single entrance hole.

Wasp traffic

A steady stream of wasps flying in and out of one hole in a wall, soffit, roof tile, bank or hedge.

The nest

A grey papery ball, golf-ball sized in spring and football-sized or larger by late summer.

Scraped wood

Fine pale scratch lines on fences, sheds and garden furniture where workers strip wood fibres for building.

Wasps indoors

Wasps appearing in bedrooms or on the landing, sometimes chewing through ceiling plasterboard from a nest above.

Crackling noise

A papery rustling or scratching from a wall cavity or loft as the colony chews and builds.

Dead wasps

Sluggish or dead wasps on windowsills in late summer and autumn.

A single queen, who has spent the winter hibernating in a shed, loft or log pile, starts a nest on her own in April or May. She raises the first batch of workers, then stays inside laying eggs while they build and forage. By late summer a nest can hold several thousand workers. All summer the workers hunt caterpillars and flies to feed the larvae, and the larvae give them a sugary liquid in return. In late summer the larvae run out, so workers turn to fruit, drinks and bins, which is when they become a nuisance. New queens and males leave in autumn, the old queen dies, and the nest is never used again.

Wasps can sting repeatedly, and a disturbed nest releases an alarm scent that sends more wasps out to defend it. Most stings mean a few hours of pain and swelling. Some people react more severely: a fast-spreading rash, swelling of the lips or throat, dizziness or difficulty breathing after a sting is anaphylaxis and needs a 999 call. Anyone with a known sting allergy should stay well away from a nest. Nests in lofts can also damage ceilings when wasps chew through plasterboard.

Common wasps have no legal protection in the UK, and a nest on your property can be treated. Any insecticide used must be approved for the job and applied as its label says; that is a legal requirement, not advice. Bees are a different matter. Honeybee swarms should go to a volunteer swarm collector through the British Beekeepers Association, and a suspected yellow-legged hornet should be reported to the authorities, not tackled yourself.

A small nest at ground level or in a shed, found early in summer, can be dealt with using shop-bought wasp powder puffed into the entrance at dusk, when the workers are home. Do not block the entrance, pour petrol or water in, or try to knock the nest down. Call someone for nests in lofts, wall cavities, under roof tiles or anywhere you would need a ladder, and for any nest if someone in the house has a sting allergy. A nest found in October or November can often be left: the colony is dying and the nest will not be reused.

We confirm it is a wasp nest and not bees, then apply an insecticidal dust or spray into the nest or its entrance. Wasps passing through carry it deeper into the nest. Activity usually drops within hours and the colony is normally dead within a day or two. Expect returning wasps around the entrance on the first afternoon, and do not block the hole: they need to go in to pick up the treatment. The nest does not have to be removed for the treatment to work, and a dead nest in a loft does no harm. Wasp nest treatment starts from £90.

1. 1Check sheds, eaves, lofts and bird boxes in April and May, when a new nest is golf-ball sized and easy to spot.
2. 2Fill gaps in soffits, fascia boards and around roof tiles before spring.
3. 3Keep bin lids shut and rinse cans and bottles before they go in the recycling in late summer.
4. 4Pick up windfall apples and plums, which draw wasps in large numbers in August and September.
5. 5Fit fly screens to kitchen and bedroom windows if there is a nest nearby.
6. 6Cover drinks and food outdoors in late summer, and look inside a can before drinking from it.

Hertfordshire's mix of suburban gardens, orchards, farmland edges and woodland suits common wasps, and nests in lofts, under roof tiles and in the eaves of Victorian and interwar houses turn up every summer from June. Dry banks along the Ver and Lea valleys and loose soil at the edges of lawns are typical sites for underground nests. European hornets also nest in the county's woodland, old trees and sheds.

Areas we cover: St Albans · Harpenden · Hatfield · Welwyn Garden City · Watford · all areas