Whitefly infestations can be controlled by encouraging the presence of natural enemies, removing the infested leaves and flies, using reflective mulch as a repellent and using traps to reduce their numbers. Insecticides and insecticidal soaps and oils can also reduce the number of whiteflies.
Release ladybugs and lacewing larvae to feed on the eggs of whiteflies, and the whitefly parasite to destroy nymphs and pupae. Inspect plants often, releasing these insects when whitefly populations are low. Avoid using insecticides that kill these beneficial insects.
Remove any infested leaves from the plant, sealing them in a garbage bag for disposal. Spray a strong burst of water on infested leaves with a water hose. This will dislodge some of the insects and drown them. You can also vacuum the whiteflies off the leaves. After vacuuming, place the vacuum bag in a sealed container in the freezer overnight. Dispose of the bag the next morning.
Mulch around the plant with a reflective plastic mulch to repel whiteflies. You may also place aluminum foil around the plant to achieve the same results.
Purchase sticky traps to place around plants, or make your own trap from a mixture of one-part petroleum jelly or mineral oil and one-part household detergent.