Posted this on the pest forum. Guess I should've put it here.
I found this, and thought it may help someone else too.
Homemade sticky traps can be built from Â¼ inch masonite attached to a stake that can be driven into the soil. Paint the masonite with bright yellow paint. Or use cardboard strips.
The adhesive can be mixed using one part petroleum jelly or mineral oil and one part household detergent. When the stickiness wears off, simply wash with soap and water, dry, and reapply homemade adhesive. Use one sticky trap for two plants and face the yellow, sticky side toward the shade.
More tips at link below.
Link: http://cals.arizona.edu/yavapai/anr/hor ... flies.html
On young garden plants, aluminum foil mulch on the soil surface will discourage whiteflies.
I'll have to look that up.