Whiteflies

HOSTS

• Greenhouse/High Tunnel Crops
• Artichoke
• Brassicas
• Cucurbits
• Hemp
• Leafy Greens
• Legumes
• Potato
• Root Crops
• Solanaceae Crops

DESCRIPTION

Adults are tiny with bright white wings and yellow-orange heads. Immature stages are inconspicuous with pale, almost translucent, flat bodies that are mostly immobile. 

BIOLOGY

Egg | Larvae | Pupa | Adult

• Several generations per year.
• Populations continue from year to year in greenhouses and in warm southern climates.

Whitefly populations continue from year to year in greenhouses and in the far south. There are several generations per year. During warm weather, on transplants, or when natural enemies are disrupted by insecticide applications, dusty conditions, or interference with ants that are attracted to the honeydew secreted by whiteflies.

SYMPTOMS

Adults and nymphs feed with piercing-sucking mouthparts, causing leaves to turn yellow, appear dry, or fall off plants. Whiteflies, like aphids, also excrete a sugary substance called honeydew, causing shiny, sticky leaves or sooty mold growth on leaves.

SCOUTING

In the greenhouse, monitor with yellow sticky cards to detect whitefly presence. Look for large colonies during warm weather on the underside of lower leaves. Honeydew may also be noticeable on the tops of leaves. Before planting, inspect transplants for whiteflies.

GENERAL MANAGEMENT

•  Attract and conserve natural enemies as they often provide adequate control.
• Inspect transplants and remove any with high whitefly populations.
• In greenhouses, use biocontrol (such as hanging cards with Encarsia sp.).
• Approved insecticides are available.

INSECTICIDES

Whiteflies develop resistance to insecticides quickly and treatment is not generally needed for garden plants in Utah. Greenhouse plants have a threshold of 10 nymphs/leaf.