Control By Water Spray
Whiteflies can be knocked off a plant with a firm spray of water. They do not easily walk back up on to the plant. Use a nozzle that makes a forceful spray that can be directed upward to hit the undersides of leaves and hard to reach stems. Do this at least 3 times--3 days in a row or every other day. Simply hold smaller houseplants upside down under the faucet in the kitchen sink.
Control By Hand Picking
When you find large numbers of whiteflies that are still in their early nymph stages, pick off the heavily-infested leaves by hand and (drop)them into a pail of soapy water. This may help control the pests long enough to allow their natural enemies to finish the job. If done early in the season, picking such leaves will not harm the plant and may, in fact, encourage it to branch and become bushier. However, avoid doing this if flower buds are forming at growing tips.
Vacuuming Trick: A neat way to keep whitefly numbers down and have some fun at the same time is to approach infested plants early in the morning with a portable battery-operated vacuum cleaner, such as a Dustbuster Plusä, and sucking the adult insects before they can scatter. Remove the dust receptacle or bag from the unit and place it in the trash or put it in the freezer for 24 hours to kill the bugs before shaking it out.
Control With Sticky Traps
Yellow sticky traps will catch plenty of whiteflies, if you don't mind them hanging in and among your landscape plants. You can buy them commercially or you can make them yourself.
Obtain some panels of a material such as Masoniteä (10 inch by 10 inch squares) and paint them bright yellow (school-bus-yellow, or Rust-Oleumä No. 659 or Sunset Yellow No. 7745), then coat the painted panels with a weatherproof adhesive_pest_product such as Tack Trapä, Tanglefoot ä, motor oil, or petroleum jelly. Then place the traps next to (not above) susceptible plants. Only use sticky traps for 3 to 4 weeks; any longer and they'll trap beneficial insects as well. Or, use sticky traps which are small plastic strips, coated with a sticky material, sold in garden centers and plant shops.
We offer a selection of aphid sticky traps in Yardener's Tool Shed; click here