Whitefly Damage on Shrubs
- Whiteflies range in size from 1/10 to 1/16 inch depending on the species. They have pale yellow bodies and white wings. Their bodies are covered in a protective waxy substance.
- Whiteflies suck juices from the shrub's foliage, creating dried-out yellow leaves and premature leaf drop. They also excrete large amounts of a sweet, watery substance called honeydew that drips on the foliage, leaving the plant sticky to the touch. A crusty black fungus called sooty mold sometimes forms on the honeydew deposits and interferes with the shrub's ability to conduct photosynthesis. The University of Missouri Extension indicates that some whiteflies can also transmit viruses.
- Gardeners control whiteflies by spraying shrubs with a steady stream of water to dislodge the insects from the plant. They encourage natural predators such as lacewings and lady beetles. They place traps that attract and catch adults or apply reflective mulches to repel insects. Insecticides have a limited effect; gardeners usually use permethrin, malathion and insecticidal soaps to control infestations.
