Whitefly

Symptoms

Injury and Symptoms of the Whitefly

  • Adults and nymphs, with piercing-sucking mouthparts
    • feed on soybean plant sap
    • inject saliva and phytotoxic enzymes into leaves
    • excrete excess liquid as honeydew onto leaves
  • Yield loss in soybeans occurs from
    • plant sap removal, wilted leaves, stunted plants
    • extensive sooty mold growing on honeydew-soaked leaves, which reduces photosynthesis
    • incomplete pod filling caused by sap removal
  • No economic threshold has been developed for soybeans

     

    Pest Status and Importance

    Pest Status and Importance

  • A minor soybean pest in most states
  • Large populations may cause plants to wilt, especially during hot, dry weather
  • Yield losses documented in Florida and Georgia, but not in Midwestern soybean fields
  • Interesting Fact: The silverleaf whitefly is a complex of at least 24 species which are morphologically indistinguishable!
    Source: Annual Review of Entomology. 2011. 56:1-19.
    Whitefly colony

    Whiteflies can develop very large colonies. Here adults and pupae of thebanded-winged whitefly are seen on velvetleaf.

    Facts

    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
    Adult silverleaf whiteflies

    Adult silverleaf whiteflies on soybean

    Whitefly nymphs

    Whitefly nymphs

    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

    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
    Silverleaf whitefly nymphs are small and difficult to see on the underside of a soybean leaflet.

    Silverleaf whitefly nymphs are small and difficult to see on the underside of a soybean leaflet.

    IPM Practices

    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
    An insidious flower bug feeding on whitefly pupae.

    An insidious flower bug feeding on whitefly pupae


    Photos and Text
    Marlin E. Rice, DuPont Pioneer
    Reviewed by Herb Eichenseer (DuPont Pioneer)