[exasperaited]

A good spray picking off the very earliest dozen or so wasps in the early spring may actually directly get the queen, who has not always permanently settled in. That point or the next few weeks is an excellent opportunity to add secondary toxins that the workers will carry in, because the nest is so small they will encounter the queen.

Beyond that I guess only completely saturating an internal trunk route through the thing with a tool like that is going to work!