Wasp pheromone remains in the air for at least 24 hours before completely dissipating.
I don’t have an exact answer, but it’s certainly more than 24 hours. This is an observation based on personal experience.
I noticed a large gray wasp or hornet nest in our yard a few years ago that wasn’t there a few weeks before.
It was adjacent to a play area for small children and was most emphatically NOT a nest of bees, so I called an exterminator who removed it.
ALSO SEE: When Is the Best Time to Spray Wasp Nest?
The following day, I went outside wearing black exercise pants to retrieve something from a different part of the yard about 50 feet from where the nest had been, and within 3-5 minutes,
I received a wasp sting directly on my butt!!! That both hurt and shocked me!!! (I’ve been told that if you’re dressed in black, they assume you’re a bear or other similar adversary.)
However, it was undoubtedly the alarm pheromones still in the air a day later that caused it to despise me, as there are plenty of wasps and hornets in the yard (as well as bees), and they all leave me alone. Therefore, at least 24 hours.
If you kill one, there is almost certainly a nest nearby. Unless you’re painting, replacing trim, or cleaning gutters (they occasionally nest in gutters during dry weather),
I’d say leave it alone. They are beneficial because their diet consists primarily of insect pests, and they are not particularly aggressive, at least in my area.
If they are nesting very close to your porch, you may need to remove the nest, but if they are simply coming and going from another location, you may be able to avoid doing so.
There are insecticide spray cans that shoot far enough to soak the nest from afar.
Do wasps and other such insects release warning Chemicals to the Hive if I Stomp on or otherwise Kill them?
When honey bees sting, and presumably the majority of closely related species such as wasps/yellow jackets and the more distantly related ants, they release a pheromone at the sting site that encourages other bees to sting the same location/target.
This pheromone can even be smelled by humans during extreme defensive situations, such as when a hive is stinging an intruder heavily. It is said to smell like bananas.
There may be a correlation between these types of alarm pheromones and sociality; solitary bees/wasps have little reason to attract others, whereas those that live in large nests have a greater chance of attracting nestmates.
When you stomp a wasp, you are potentially releasing any stored pheromones in its glands. In a sense, stomping a wasp will release the alarm pheromone into the air, but it will be a confusing signal mixed in with a large number of other pheromones.
Additionally, it will lack the location specificity associated with being on the target, you.
You have been stung for a reason your entire life. You may be unsure of the reason. Any wasp or bee stings primarily to defend its nest.
What you define as staying away from the nest and not bothering it may differ from what the insects define as staying away.
You state that the nests are located near the workshop. Because bees/wasps do not react well to vibration, running power tools that vibrate a lot and agitate them, followed by walking by the nest, could very well be all that is required to get stung.
Although I did not smell the bananas, I can attest that swatting a wasp attracts others. I stepped on a wasp nest accidentally last year, and they attacked me “en masse.”
The same thing happened to me as a child, and my instinct was to flee as quickly as possible, escaping with only one sting.
This time, as a tough (?) grown man, my instinct was to stand my ground and fight, and boy was I wrong.
I was stung a dozen times, and some of the wasps were clever enough to crawl under my clothes, increasing the effectiveness of their stings and also making them more difficult to kill.
Additionally, along the path back home,
I would occasionally encounter a wasp buzzing around me, most likely attracted by the odor released by the trapped wasps under my clothes.
Fortunately, I was able to wave these ones away without being stung.