|Freeman, Thomas - NORTH DAKOTA STATE UNIV|
|Gerling, Dan - TEL AVIV UNIV, ISRAEL|
Submitted to: Entomology International Congress
Publication Type: Abstract Only
Publication Acceptance Date: March 28, 2000
Publication Date: N/A
Technical Abstract: Whiteflies are a problem in greenhouses and many economically important plants worldwide. The silverleaf whitefly, Bemisia argentifolii, is particularly devastating. Our recent findings showed that both the adult and nymphs of the silverleaf whitefly can reach phloem bundles for feeding from any position on the leaf, contrary to previous theory. This is believed to be true for any host plant and true for the greenhouse whitefly, Trialeurodes vaporariorum, the giant whitefly, Aleurodicus dugesii, the spiralling whitefly, Aleurodicus dispersus, and a recently discovered New World whitefly on the Canary Islands, Lecanoideus floccossimus. The labium of the feeding apparatus consists of four segments; the first attached to the thorax, and the three distal segments with a deep longitudinal groove which contains the stylet used to penetrate the leaf and feed on the phloem sap. The length of the labial groove contained within the three distal segments, two, three and four, is equivalent to the length of the stylet. Thus, the length of the stylet can be determined by measuring the total length of the three distal segments. This length represents the maximum distance that the whitefly can penetrate the leaf in search of a phloem bundle. The average length of the stylets was: B. argentifolii 210 um, T. vaporariorum 272 um, A. dugesii 391 um, A. dispersus 302 um, and L. floccissimus 357 um. All of these adult whitefly species had similar appearing abdominal wax plates. They produced and shed waxy particles consisting of long-chain aldehydes and long-chain alcohols of which the major component, depending on species, is 30, 32 or 34 carbons.