Whiteflies are becoming a problem in just about every state north of the Gulf Coast up to about Kentucky. Any location with suitable hot weather can develop an infestation. The most effective measures to limit damage are to eliminate common hiding places and remove plants that are alternative hosts. Spraying can be effective in some circumstances, but there are always more whiteflies to re-colonize an area.
Some work at Waginengen was discussed here a few times over the last 10 years indicating resistance breeding is viable. It is worth a look at the original papers.
https://www.academia.edu/6874956/Res...wild_relatives
Look at the bottom center of the page for a button to read online or you can download the pdf.
Here are some alternate links I've used before.
http://edepot.wur.nl/215863
http://edepot.wur.nl/222200