The adult White Fly is not the real problem, but is an indication that you also have larva and they are the problem. Yellow sticky traps, used to monitor a problem, can be used to somewhat limit the number of Adults flying around which wil lthen limit the number of eggs that are layed which will then limit the number of larva you have, any Adults you trap will be a good thing.
If you can see where the larva are, an insecticidal soap sprayed on them can help reduce their numbers, but the best control is to encourage predators to move in and chomp on these wee buggers, so due care using any spray or dust is necesary.

Here is a link that might be useful: Whitefly control

Neem oil applications can be extremely helpful in whitefly control. The nymphs, which often look like small opaque disks on the underside of the leaves, will be halted in their development and will not be able to evolve into adults. You will not have an immediate kill of whitefly adults, but the longer term results will be satisfactory.