Pest control companies around the city say they are dealing with an influx of wasps and some residents say the irritating insects are invading Calgary communities like never before.

Wasps are a common summer pest and for some the sting can be dangerous and even fatal.

If a fertilized queen survives the winter, she will start a colony in the spring by building a small nest for her starter female workers. Those worker wasps will then expand the nest so the queen can keep laying eggs and by the end of the summer, more than 5000 wasps will inhabit the colony.

In a few neighbourhoods in the city, the wasps seem to be out of control now that the warmer temperatures are here.

"Several people are suffering multi-stings not just one or two because they're really wickedly angry right now" said Kath Smyth from Goldengate Garden Centre. "It's been too cool and too wet and now its hot and its dry and its time for them to get out there."

James Borrow is the Integrated Pest Management Lead for the City of Calgary and says this is a pretty typical year for wasps.

“Typically in a warm season you’re going to have more wasps than in a cold season and typically at this time of the year is when people start noticing wasps in and around their homes because the population in the nest has grown to such an extent that they start to deplete the resources in the area and they’re typically predatory so they’ve been out eating up all the garden pest insects and then they start to look for other food sources so if you’re out in your backyard with a nice, sweet drink, they can smell that and they’ll come up and try and have a drink too,” said Borrow.

Borrow says the city doesn’t keep track of numbers and only removes nests that are creating a danger to the public.

“We always get a few calls about wasps and we do remove wasps from areas where we expect people to congregate so if we find out there’s a wasps’ nest in a playground setting or something like that then we’ll go out and remove them otherwise we typically don’t do anything about them,” said Borrow.

The city says there are a few things people can do to keep wasps away:

  • Keep screens for doors and windows in good repair. Seal any potential entry points such as window cracks, doorframes and vents
  • Place garbage into a bin or can with a lid that is well fitting
  • Destroy abandoned animal burrows (e.g. gopher holes) before wasps inhabit them. It is common for ground nesting wasps to use such structures as a nest location
  • Cover and/or remove food wastes to reduce wasp encounters. Food sources left outdoors in the form of compost piles, animal food and leftovers from picnics and barbecues are attractive to wasps in spring and early summer when they seek protein-based foods
  • Keep food containers closed and pop/juice drinks covered. In late summer and early fall when food supplies are dwindling, male and worker wasps scavenge for food and may act aggressively while in pursuit of sweet tasting food
  • If you have fruit trees in your yard, remove all over-ripened or rotting fruit lying on the ground or attached to a branch.

The city says different procedures should be employed to remove nests depending on where they are located.

For ground nests, cover the entrance with a large clear bowl or pack with soil so that the wasps become entombed. Home owners can also pour soap and water into the nest entrance.

Concealed nests are often found in hard-to-reach areas like foundations and attics so it is best to contact a pest control company to deal with it.

Exposed nests can be dealt with by spraying the entrance with wasp or hornet repellant.

If you chose to remove an exposed nest, make sure you wear protective clothing and put the nest in a cloth or plastic bag. The bag can then be put in the freezer, in direct sunlight or submerged in water to kill the wasps.

Experts say that wasps do not reuse an old nest and it is best to remove them in the winter or spring.

Borrow says wasps are not just pests but are also good for your garden.

“They do have some benefit in the garden environment because they are predators and they do cleanup those insects that we commonly think of as plant pests,” said Borrow.

For more information on pest management, visit the City of Calgary website.