This is a photo of a wasp nest I treated before the kitchen roof was removed by builders. The customers called me back as when the roof was removed it revealed the under section of the nest. In this section alive wasps where seen.
The wasp nest is basically fully treated. The insecticidal dust had reached all areas of the nest killing all the adults. The only areas protected from the insecticidal dust is the chambers where the wasp larvae have pupated to become adults. The new adults emerge from the pupae in to a deserted nest which is still full of residual insecticide. Its only a matter of time before the insecticide kills them too.
As the builders at this particular site refused going back to work until the nest was removed, a liquid insecticide was applied so it'd soak through to the remaining larvae.
You can see the white chambers to the right of the nest which still contain grubs/pupae.
Pest Control Wirral, Chester and Ellesmere Port