root aphids are difficult
some things that work are
clean bomb clean, reduce to a few moms if possible
mightywash drench/DUNKS (the less soil you have the better), repeat if nessicary
or use chemi imidi (merit 75 or bayer) moms
take clones, remove all soil after roots appear.
clean bomb clean
use a preventative like MET 52, i used no fly last season and didnt get them. using MET now and i got gnats.
wish there was a one product keep all bugs away orgnaic solution.