Identify Your Pest Flying insects Yellowjacket
Yellowjacket
Vespula and Dolichovespula spp. · Also called: Yellow jacket, wasp, ground wasp, meat bee
Yellowjackets are small, smooth black and yellow wasps that build covered paper nests in the ground, in walls or under eaves. People notice them most in late summer, when workers crowd garbage, patios and sweet drinks and defend their nests hard.
Size About 12 to 16 mm long
Colour Bright yellow and black bands on a smooth, shiny body
Key feature Smooth, nearly hairless body with sharp yellow and black bands
Season Spring to the first hard frost; busiest in August and September
Where Ground holes, wall voids, sheds, under decks and near garbage bins
What it looks like
Yellowjackets are compact wasps about the length of a thumbnail. The body is smooth and shiny, with bold yellow and black bands, a thin waist and very little hair. At rest the wings fold lengthwise along the sides. They fly fast, often in a side to side pattern, with the legs tucked up.
The nest is the clearest clue. It is a grey paper nest wrapped in layers and hidden from view, so you usually see only a stream of wasps flying in and out of one small hole. Watch for that steady traffic at a gap in the lawn, a crack in siding, a vent or a space under a deck step. Aerial yellowjackets, also common in Alberta, hang a covered grey paper ball from eaves or shrubs instead.
Often confused with
Honeybee
Paper wasp
Hover fly
Signs to look for
Steady traffic at one hole
Wasps at food and garbage
Rustling inside a wall
Wasps indoors in late summer
Risks and damage
Yellowjackets can sting more than once, and a disturbed nest can send out many defenders at the same time. For most people a sting means pain, redness and swelling that fade within a few days. People with a venom allergy can have a serious reaction and need medical help right away if they have trouble breathing or swelling of the face. A nest inside a wall can grow large, and workers sometimes chew through drywall into a room.
In Alberta
Several yellowjacket species live across Alberta, in Edmonton, Calgary, Red Deer and rural areas. Queens start nests in spring, colonies peak in August and September, and workers die after the first hard frosts. Only young queens survive winter, in sheltered spots such as leaf litter or wall gaps.
Yellowjackets are useful predators. Through spring and summer, workers hunt flies, caterpillars and other insects, then chew them up to feed the growing larvae back in the nest.
How to keep them out
Cover food and drinks outside
Keep garbage sealed
Seal gaps before spring
Fill old burrows
Pick up fallen fruit
When it is time to bring in a professional
Professional help is worth it when a nest is inside a wall, attic or soffit, close to a door or play area, or in the ground where people walk. It also makes sense if anyone in the home has a sting allergy. Technica’s licensed technicians can locate the nest entrance and deal with the colony safely.
Frequently asked questions
Will a yellowjacket nest come back next year?
The old nest is not reused. The colony dies after hard frosts in fall, and new queens start fresh nests each spring. A spot that suited one nest may attract another, so sealing gaps in late fall and filling holes in early spring helps.
Why do yellowjackets seem so aggressive in late summer?
By August the colony is at its largest and many workers are searching for sugar. That brings them to drinks, fruit and garbage, and more wasps near people means more stings. Moving slowly and not swatting lowers the risk.
Should I plug the hole where the wasps go in?
No. Blocking an active entrance, especially in a wall, can push the wasps to chew a new way out, sometimes into the house. Keep people away from it and have the nest dealt with first. The gap can be sealed once the nest is gone.