by National Gardening Association Editors
An adult whitefly is typically 1/16" long.
This pest is found throughout the United States. The tiny insects feed in large numbers by sucking plant juices from the leaves and stems of many plants, including tomatoes, cucumbers, lettuce, flowers, trees, and shrubs.
Whiteflies secrete a sticky, sugary substance called honeydew that may cause the growth of a sooty black fungus on leaves. Eggs laid on leaf undersides hatch into tiny larvae that look like flat, oval, semitransparent scales. The larvae reach adulthood within a about a month of hatching.
Spray plants with a stream of water from a garden hose to dislodge the majority of the pests before applying insecticidal soap or other approved product. For effective control, follow instructions on the product label for an appropriate spray schedule.
Whiteflies cannot survive freezing temperatures. They are reintroduced to northern regions each year on the wind and infested plants. Check plants carefully for whiteflies before purchasing.
Photography by Jeffrey W. Lotz, Florida Department of Agriculture and Consumer Services, Bugwood.org