Homeowners are being urged to take extra care around wasps this September, as a pest control expert explains why the insects become noticeably more aggressive as summer draws to a close. While wasps are a common sight throughout the warmer months, their behaviour changes significantly during September as colonies reach the end of their natural life cycle.
Earlier in the summer, worker wasps spend much of their time feeding larvae inside the nest. In return, the larvae produce a sugary substance that provides the workers with food. As the season draws to a close, the queen stops laying eggs and the number of larvae rapidly declines, leaving thousands of worker wasps searching elsewhere for sugar.
Why wasps become more aggressive
This is why wasps become far more attracted to bins, soft drinks, outdoor dining areas and fallen fruit during September, leading to more encounters with people.
John Whiteley-Wilkson, managing director at Acorn Environment Services, said: "September is consistently one of our busiest months for wasp call-outs because colonies are at their largest and worker wasps are actively searching for food outside the nest. People often think wasps suddenly become aggressive for no reason, but it's a natural part of their life cycle. As their usual food source disappears, they're forced to search elsewhere, which brings them into much closer contact with people."
Common DIY mistakes to avoid
John is also urging homeowners to avoid trying to deal with active nests themselves, warning that DIY attempts often make the situation worse.
He said: "The biggest mistake we see is people trying to block the entrance to a nest or treating it with a household aerosol spray. If wasps can't use their normal exit, they'll simply look for another route, which could mean finding their way into lofts, wall cavities or even inside the property. Disturbing an active nest can also cause the colony to become defensive, increasing the risk of multiple stings."
Acorn Environment Services said there were several mistakes homeowners should avoid if they discover a wasp nest:
- Blocking or sealing the entrance to the nest.
- Spraying large or established nests with household insect sprays.
- Disturbing the nest with garden tools, ladders or pressure washers.
- Attempting to knock down or remove the nest themselves.
- Carrying out garden maintenance close to a known nest without checking activity first.
John added: "Even activities like cutting hedges, strimming or using a pressure washer can create vibrations that disturb an active colony. We've attended plenty of jobs where someone didn't realise there was a nest nearby until the wasps reacted."
When to seek professional help
While not every wasp nest requires immediate treatment, John said homeowners should assess the location carefully before deciding what to do.
He said: "If a nest is tucked away in a part of the garden that people rarely use, it may be possible to leave it alone until the colony naturally dies off later in the autumn. However, if it's close to a doorway, patio, children's play area or anywhere people regularly pass, it's worth having it professionally assessed rather than taking unnecessary risks."
With warmer weather often continuing well into September, Acorn Environment Services said it expected wasp activity to remain high for several weeks before colonies begin to naturally decline later in the autumn.
