page_title: Silverleaf whitefly
section_title: Anatomy and life cycle
hierarchical_section_title: Silverleaf whitefly / Anatomy and life cycle
caption_attribution_description: Bemisia argentifolii Common Name: silverleaf whitefly Photographer: Scott Bauer, USDA Agricultural Research Service, United States Contact: USDA ARS Photo Unit, USDA Agricultural Research Service Descriptor: Adult(s) Image taken in: United States
context_page_description: The silverleaf whitefly is one of several species of whitefly that are currently important agricultural pests. A review in 2011 concluded that the silverleaf whitefly is actually a species complex containing at least 24 morphologically indistinguishable species.
  The silverleaf whitefly thrives worldwide in tropical, subtropical, and less predominately in temperate habitats. Cold temperatures kill both the adults and the nymphs of the species. The silverleaf whitefly can be confused with other insects such as the common fruitfly, but with close inspection, the whitefly is slightly smaller and has a distinct wing color that helps to differentiate it from other insects.
  While the silverleaf whitefly had been known in the United States since 1896, in the mid-1980s an aggressive strain appeared in poinsettia crops in Florida. For convenience that strain was referred to as strain B, to distinguish it from the milder infestation of the earlier known strain A. Less than a year after its identification, strain B was found to have moved to tomatoes, and other fruit and vegetable crops.
context_section_description: Female B. tabaci will lay 50 to 400 eggs ranging from 0.10 mm - 0.25 mm on the under part of leaves. Female whiteflies are diploid and emerge from fertilized eggs whereas male whiteflies are haploid and emerge from unfertilized eggs. Eggs are laid in groups, being small in size with dimensions of 0.2 mm wide and 0.1 mm in height. Eggs are initially whitish in color and change to a brown color near hatching, within 5 to 7 days. After hatching, the whitefly nymph develops through four instar stages.
  The first instar, commonly called a crawler, is the only mobile nymphal stage. The first instar nymph can grow to about 0.3 mm and is greenish in color and flat in body structure. The mobile nymph walks to find a suitable area on the leaf with adequate nutrients and molts into an immobile stage.  The next three instars remain in place for 40–50 days, until molting into an adult. Silver exuvia, or shed skins are left on the leaves. The immobile instars appear opaquely white. Nymphs feed by stabbing into the plant with their mouth-parts and sucking up plant juices. After the fourth instar, the nymph transforms into a pupal stage where the eyes become a deep red color, the body color becomes yellow, and the body structure thickens. This is not a true pupal stage, as is found in the Endopterygota, but is similar in function. Adult whiteflies are approximately four times the size of the egg, with light yellow bodies and white wings, which is attributed by the secretion of wax across its wings and body. Adult silverleaf whiteflies can reach up to 0.9 mm in length. While feeding or resting the whitefly adult folds its wings tent-like over its body.
caption: Bemisia tabaci molting on leaves. The silver empty structures on the leaves are cast-off skins.
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