pests and diseases
Whitefly
Last reviewed 2026-10-04
A whitefly is a small sap-feeding insect that often gathers on the undersides of leaves. Adults may fly up when a plant is disturbed, while immature stages remain attached to leaves. Feeding can weaken plants, produce sticky honeydew, and contribute to sooty mold or virus spread.
What it means
Whiteflies are not true flies. Several species affect vegetables, ornamentals, and houseplants. Their appearance and control can vary, so identification matters. Warm conditions can support rapid population growth.
How it affects the garden
Inspect leaf undersides and monitor before deciding whether action is needed. Remove badly infested leaves when practical, use physical controls for suitable plants, and protect natural enemies. Repeated broad-spectrum sprays can disrupt beneficial insects and may not reach hidden immature stages.
Use IPM: identify the insect, estimate damage, and choose a targeted response. The can I grow this tool can help review environmental fit, but it cannot diagnose a pest from a general symptom.
Example
A group of small insects rises from the underside of a cucumber leaf when it is shaken. The gardener checks nearby leaves and looks for honeydew and natural enemies before choosing a response.
Common confusion
Whiteflies are different from fungus gnats, which are usually associated with moist potting mix and fly around the soil surface.
Sources
University of Minnesota Extension explains whitefly identification and management.
