White fly is hard to get rid of. While vacumning the adults up is one solution I've heard of, it doesn't do much for the other life stages , eggs and nymphs that are still doing their thing. That's what makes controlling white fly so difficult, whatever it is you do you have to keep doing in succession for a period of weeks, every three to four days. Some things to try...Sunspray or Safers soap, mixed according to lable directions and sprayed to the point of run off, especially the undersides of the leaves where the varmits hide, will sometimes help, if you're really committed to a rigid spray schedule.
This late in the season, maybe, depending on which
plants are infested, a good freeze would be welcome. I've been frustrated with white fly before, let the salvia I was having problems with, totally unprotected so the tops froze back, cleaned up the mess. the following
spring, white fly was gone.