Yellowjackets are wasps belonging to the genera Vespula and Dolichovespula. While there are many wasp species in the Edmonton area, most are non-colonial, do not construct paper nests and generally do not (or cannot) sting. While yellowjackets are capable of stinging in self defence, the level of terror expressed by the average picnic-goer is usually far in excess of the danger they represent.
Most people typically encounter yellowjackets when they are outside having a meal. The workers, out searching for food sources for the colony, are attracted to meats and sweet beverages, typical fare at a summer barbecue. Other likely situations where an encounter occurs are at cleanup time as they may be inside empty pop cans, poking around in poorly-tied garbage bags or in the immediate proximity of fruit trees, especially in the fall. The usual response of swatting to the insect invader may provoke a defence response in the wasp in the form of a sting. Unlike honeybees, which can only sting once due to a barbed stinger, wasps can sting multiple times. The sting itself usually only produces minor pain, however a medical professional should be consulted if any symptoms more serious than local swelling and mild pain occur. The best reaction? Stay calm and gently shoo the wasp away. If it does not feel threatened, it should not sting.
In addition, agitated wasps, even while dying, typically release alarm pheromones that are chemical signals detected by other nearby wasps and induce aggressive behaviour. In some cases, when people claim to have been stung “for no reason”, what has likely happened is that a yellowjacket has been unknowingly swatted, squished, or stepped on, causing it to send out the alarm to its siblings. Agitated yellowjackets will sometimes attack in numbers under such circumstances, especially if the nest is particularly close by or under direct attack. This is all the more reason to treat your insect neighbours with care and respect.
What You Can Do
To remove a wasp nest yourself, proceed with care. The first step is finding the nest. If it isn’t obvious, leave food out and follow it back to its nest. If the nest is free-hanging from a tree branch, removal will be easier. Proceeding carefully at dusk, you may be able to wrap the nest in a sturdy plastic bag and remove it one fell swoop. Avoid shining a bright light on the nest or otherwise disturbing it. Seasonal timing is also of concern. If you find a yellowjacket nest early in the spring and it is in an inconvenient location, removing it earlier rather than later is best when there are fewer wasps to deal with than in the fall. Nests are not re-used in following years.
If the nest is more firmly attached to a solid structure or is subterranean (they are often constructed under the edges of sidewalks), removal of the nest may not be possible. Other simple and effective methods include using plastic bowls (preferably yellow) filled with soap-laced sugar water. The wasps will be attracted to the colour and scent, will fall into the water and will drown. When in doubt, seek a professional pest management removal company.