Unfortunately, yes, we agree the pictured symptoms definitely indicate Aster Yellows infection. You do not need to dig everything up...just remove the symptomatic plant. This pathogen that acts a bit like a virus is spread through the mouthparts/saliva of feeding leafhoppers (not all of them, just a certain species) and that insect arrives anew in our region every year as they migrate (or blow on air currents or storms) back north each season, so there is no way to eradicate them long-term from gardens. Removing infected plants, however, along with any weeds in the immediate area, will reduce the odds of an infected perennial plant harboring the pathogen for easier leafhopper transmission to other desirable plants in a future year.

Miri