Yellow sticky traps and soapy water are effective against white flies. I once planted nicotiana as a trap to keep white flies away from the roses which worked well.

White fly needs a host plant to reproduce. Here in the south the usual culprit host plant is privet(Ligustrum) especially the variegated type. If that is growing in your yard, get rid of it. Your problem should be solved...unless it is growing on your neighbor's property.

No privet here or anywhere around. They seem to have made the potatoes their home.

I like the soapy water idea.

That is my favorite all around solution.

As a side note, how destructive are they? This is my first experience with them.

Depending on how many there are, they can be very destructive. Last summer all of the celandine poppies that have naturalized at the edges of the beds and borders here were inundated with whiteflies. These aren't an important plant for me, but nevertheless, I paniced seeing literally millions, tens of millions of whiteflies on the poppies. Then I sprayed a bunch with soapy water, hung some yellow sticky traps which killed some but there were far too many. Realizing the whiteflies only cared about the poppies, I stopped doing anything but seeing what would happen next. Whiteflies suck the juices from plants and leave a sticky residue turning the leaves brown. None of the plants died as a result, but looked really sickly. I'm wondering if they'll come back this summer.

I did a search and found this site explaining whitefly problems.

Here is a link that might be useful: ucdavis

Thanks Althea.

I did some looking around and didn't come up with a lot.

Thus, my reason for posting here.

White Flies are a new thing for me.

There was a thread on the tomato forum (I think) a year or two ago that suggested using Pantene clarifying shampoo as your soap for spray. Supposedly works well, but I can't say from experience. Also, I have read that using seaweed spray has some effectiveness.
Mrs H

Follow-up on the Pantene/ seaweed spray suggestion:

I tried a mixture of Pantene clarifying shampoo and seaweed spray using about two tablespoons of seaweed liquid and a "good squirt" of shampoo in a gallon of water, and sprayed with a pressure sprayer. Since then, I have seen two or three whiteflies total. Since they multiply rapidly, I'll probably apply another one or two treatments. I didn't have them in biblical proportions yet, but they were causing some yellowing of squash plant leaves, and there were lots of them in the tomatoes.
Mrs H