Injury and Symptoms of the Whitefly

No economic threshold has been developed for soybeans

Pest Status and Importance

Facts

• Common names: whitefly, silverleaf whitefly, sweetpotato whitefly
• Latin name: Bemisia tabaci, family Aleyrodidae
• Description
  • Adult: yellowish body with snow-white wings and red eyes; length is 0.03 inch (0.8 mm)
  • Nymph: first instar is called a crawler; there are 4 instars, the last stage being 0.6 mm in length
  • Egg: microscopic in size and laid in clusters on the underside of leaves

Origin and distribution

• Silverleaf whitefly has a global distribution, but originally occurred in the Middle East-Asia Minor region
• A global invasion occurred in the late 1980s, primarily via trade in ornamental plants
• First reported in soybeans in Florida during 1988

Life History

• Females lay 50-400 eggs on the underside of leaves
• First-stage nymphs (crawlers) move away from the hatching site, settle down to feed, and become immobile (stop crawling)
• There are 4 nymphal stages
• Development occurs between 57 F and 97 F
• Generation time is 22 days (range 18-50 days)
• Silverleaf whiteflies have been recorded from over 500 plant species including many vegetables, ornamentals and cotton
• Multiple generations occur per year

Integrated Pest Management Practices

• Recommendation: spraying solely for whiteflies is probably not economically profitable; consider an insecticide if soybean aphids or two-spotted spider mites are also present and extended hot, dry weather is forecast
• Insecticides: products containing bifenthrin may provide the best control of whiteflies in soybeans
• Plant resistance: no known resistant soybeans
• Biological control: some predators will prey on whitefly nymphs and pupae, but beneficial insects cannot be expected to quickly suppress large populations