Consumer wasp sprays are designed for aerial nests — the kind you can see and aim at directly. Underground nests are a completely different situation. The tunnel system of a yellowjacket colony can extend well below the surface, with the queen chamber deep enough that a surface spray never reaches it.
You might kill the workers coming and going, but the colony survives, the queen keeps laying, and now the nest is agitated on top of being intact. Professional ground wasp removal in New York City uses insecticidal dust and soil injection products that penetrate deep into the tunnel structure. The goal isn’t to knock down the workers at the entrance — it’s to reach the source.
That’s the only treatment that eliminates the colony rather than temporarily disrupting it. We also treat at the right time, using the right protective equipment, because doing this job safely is not optional. The NYC Department of Health puts it plainly: it is dangerous to attempt nest removal yourself, and it is the responsibility of property owners to address wasp nests on their property. We handle both sides of that equation.