Wasps Most Aggressive in September After Hot Summer, Pest Expert Says — How to Avoid Stings

Wasps across the UK are entering a more aggressive phase as colonies near the end of their seasonal cycle, a pest control expert warned, and people planning outdoor activities should take simple precautions to reduce the risk of being stung.

James Copley, director of Copley Pest Control, said an unusually warm spring followed by the hottest summer on record produced a population explosion among common garden wasps. He said the insects become particularly aggressive between August and early September as nests age and food sources change.

Copley explained that between August and early September queen wasps normally stop laying eggs and the nest begins its end-of-life phase. As larvae disappear and stored food sources dwindle, worker wasps shift from gathering protein for larvae to seeking out accessible, carbohydrate-rich foods. "As natural food sources decline, worker wasps are under pressure to find food, which makes them more aggressive and more likely to sting you," he said.

Pest-control guidance for avoiding encounters with foraging wasps focuses on reducing attractants and limiting easy access to sweet foods and drinks. Covering food, keeping sugary beverages in sealed containers or cans, and clearing up spills promptly can lessen the chance of wasps approaching outdoor dining areas. Keeping garden bins closed, removing fallen or overripe fruit from trees, and storing pet food indoors are also recommended measures.

Experts advise that people who find a nest on or near their property should avoid attempting to remove it themselves, particularly while worker activity is high. Professional pest controllers can assess the size and location of a nest and recommend safe removal or containment when appropriate.

The seasonal surge in wasp activity comes amid broader patterns linking insect populations to weather. Warmer-than-average temperatures can accelerate colony development and lengthen the active season for some species, leading to higher numbers later in summer. In the UK this year, the combination of an abnormally warm spring and a record-breaking summer contributed to higher-than-usual wasp sightings reported in gardens and public spaces.

Public-health officials and pest specialists note that while most wasp encounters result in defensive stings rather than aggressive attacks, certain situations increase the risk of stinging. Rapid movements near a nest, swatting at wasps, or disturbing a nest can provoke defensive behavior. People who are allergic to wasp venom should carry appropriate medication, such as an epinephrine auto-injector, and seek immediate medical attention if stung and symptoms of a severe allergic reaction develop.

As the season progresses toward autumn, Copley and other pest professionals expect worker activity to remain elevated until nests naturally collapse and the colonies die off with the first frosts. Until then, simple housekeeping and sensible behaviour while eating outdoors are the primary recommendations for reducing unwanted encounters with wasps during the last weeks of warm weather.