I found a great Whitefly Repellent... Neem Meal, also called Neem Cakes or Neem Manure. Neem Oil is a peasant crop, meaning it is the sole source of income for a large population in India. Neem bushes grow wild throughout India, and are never sprayed because it is a natural pesticide. The Neem Seeds are collected and the oil is removed using hand-presses, much like a cider press. The remaining seed casings and residue is pressed into a round cake. Neem is an ideal fertilizer, since it contains ideal balances of NPK and micro-nutrients. The extracted oil is sold as Neem oil, while the Neem byproduct of cakes are sold as a fertilizer. I use the Neem meal as a pesticide, sprinkling it on the soil of my potted plants. It doesn't kill the bugs, but it makes them want to relocate.
http://www.groworganic.com/neem-seed...-6-lb-box.html
I use it in my greenhouse for Whitefly and Aphid control, and also sprinkle it around the base of my young cucumber plants to get rid of cucumber beetles in my garden. I had an epidemic of cucumber beetles to the point that I gave up growing Cukes. Then I discovered Neem Meal. A little goes a long way, and it holds up rather well in weather. Unlike Neem Oil, it dissolves slowly when watered or wet. The nice part is that as it dilutes, it feed the plants.