Wasps have started to bother my family as we have dinner on the deck attached to our apartment. We've been lucky that they seem to have arrived late, but they have returned and are especially attracted when we are grilled meats on the barbecue.
According to my favourite phone app, INaturalist - which lets you take picture of a plant or animal and then its machine learning algorithm will try to identify it for you - they are yellowjackets. So I've begun to look into traps. A few things to consider:
One that I found available at Home Hardware is called the "RESCUE Disposable Yellow Jacket Trap" which describes itself as:
What could this attractant be? Reading the back, it is heptyl butyrate, which is "found abundantly in fresh apples and plums" [source] :
High school chemistry students will know this as an ESTER, with IUPAC name heptyl butanoate (C3H7COOC7H15). It's an ester because of the carbon atom with a double bonded O *and* a single bonded O *and* the single bonded O has more carbons attached to it on the other side.
They claim that bees are not attracted to this particular chemical.
Unfortunately, this chemical only attracts a single species of yellowjackets, called the Western Yellowjacket (Vespula Pensylvanica), which is the most common yellowjacket on the west coast of North America (for example, California). Here in Toronto, Ontario, we also have German yellowjackets (Vespula Germanica) and the common wasp (vespula vulgaris).
In fact, 2016 research aiming to find out exactly why heptyl butyrate is attractive to yellowjackets was done in Washington State, so likely targeted vespula pensylvanica by chance. If you're looking to find out exactly what type of yellowjacket you have in your area ... it is likely to be many possible kinds but I haven't yet figured out how to tell from the markings on their back.
Conclusion: I do *not* recommend this yellowjacket trap for use in Toronto, Ontario.