Hi Laura,

The easiest thing to do is to wait--that nest will not survive through the winter and should go away as soon as we have a good freeze.  Only the new queens survive the winter and will look for new nest sites next spring.  Spring is the best time of year to hang out the traps for this reason--catching the new queens and first few workers is much more effective than trying to eliminate hundreds or thousands of workers late in the season.

To try to eliminate them more quickly, you can use an insecticide labeled for outdoor use on yellow jackets (like a foaming wasp spray, etc).  Apply it when temperatures are cool and/or at night for safety.  It can be difficult to eliminate established nests with insecticides because it is virtually impossible to treat the whole nest underground, but a persistent product applied at the nest entrance could make a difference.  Be sure to read and follow the label directions on all insecticide products.

This CSU Fact Sheet contains more information:https://extension.colostate.edu/topic-areas/insects/nuisance-wasps-and-bees-5-525/

and see also: https://webdoc.agsci.colostate.edu/bspm/arthropodsofcolorado/Yellowjackets.pdf

I hope this is helpful!

Cordially,

John