The only way I can think of doing it on the cheap is to dig a bigger
hole and roll them in. Let the termites take care of them.

Bad idea. Even if the main colony of termites doesn't attack his
house from where they are, the next swarm could put 10 colonies along
his stem wall, three inside and five at his neighbor's house. The
entire neighborhood will be panicked when they see termite alates
(queens and kings) on their windowsills both inside (some will get
lucky and fly in) and outside... and guess who they're going to blame
it on.

Dig up the root balls. Get what you can of the roots. Chop them up
with an axe (being sure not to hit any pvc pipe underground) and throw
them away.

alt.consumers.pest-control