Whiteflies

Bemisia tabaci

Description

Adult whiteflies are very small insects, approximately 1.5-2 mm in length, with four powdery white wings. When plants are heavily infested, one may notice a “cloud” of tiny white insects rising above it.

Life Cycle

whiteflies have five distinct stages of development. Eggs are laid on the undersides of the youngest leaves and hatch in 5 to 7 days. The crawler is the small and translucent stage that walks a short distance before settling at a feeding location. Shortly they transform to the sedentary scale stage. The scale is a highly modified sucking insect, and its outer covering gives it added protection. Pupation occurs within the scale cover and adults emerge in four days. The entire whitefly life cycle takes about 3 weeks, depending on temperature, allowing populations to build quickly.

Damage

All stages of whiteflies feed on plant sap using piercing-sucking mouthparts. As whitefly infestations become severe, plants become yellow and lose their leaves. Whiteflies produce sticky, sugary honeydew on leaves which causes black sooty mold to colonize and reduce the attractiveness and marketability of the crops. Even worse, whiteflies are vectors that transmit plant viruses from infected plants to healthy plants.

Control

Advice

Add 1 tablespoon of liquid dish soap to one gallon of water and mix well. Spray the upper and undersides of leaves in cooler temperatures; late in the day is best.

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