How to Manage Pests

UC Pest Management Guidelines

DESCRIPTION OF THE PEST

Silverleaf whiteflies are small insects about 0.06 inch long. The body and wings of adults are covered with a fine, whitish powdery wax, opaque in appearance. Whiteflies colonize on the underside of leaves. Adults and eggs are commonly found on the lower surface of younger leaves, and the scalelike nymphal stages on somewhat older leaves. Clouds of small white insects fly up when plants are disturbed.

DAMAGE

Silverleaf whiteflies generally are not a serious problem in beans. When present, infestations are frequently restricted to small areas and to the field edge. Infested leaves will be slightly curled and copious quantities of honeydew may be deposited on leaves, resulting in a sticky, shiny appearance.

MANAGEMENT

Biological Control
Several wasps, including species in the Encarsia and Eretmocerus genera parasitize whiteflies. Whitefly nymphs are also preyed upon by bigeyed bugs, lacewing larvae, and lady beetles. Silverleaf whitefly is an introduced pest that has escaped its natural enemies. Some indigenous native parasites and predators do attack it, but do not keep it below damaging numbers.

Organically Acceptable Methods
Biological control is organically acceptable.

Treatment Decisions
Chemical treatments are not recommended for silverleaf whitefly on dry beans.

PUBLICATION

UC IPM Pest Management Guidelines: Dry Beans
UC ANR Publication 3446
Insects and Mites
L. D. Godfrey, Entomology, UC Davis
R. F. Long, UC Cooperative Extension, Yolo Co.

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