|Freeman, Thomas - NORTH DAKOTAT STATE UNIV|
|Chu, Chang Chi|
Submitted to: National Research and Action Plan for Silver Leaf Whitefly
Publication Type: Abstract Only
Publication Acceptance Date: December 18, 1998
Publication Date: N/A
Technical Abstract: Whitefly eggs are generally elongate-oval and the basal end has a pedicel or stalk of varying length by which the female attaches the egg to a plant leaf. Using established methods for leaf tissue fixation, embedment, sectioning and staining, the penetration characteristics of silverleaf whitefly (Bemisia argentifolii) eggs inserted into cotton leaves were observed by both light and transmission electron microscopy (TEM). Scannin electron microscopy (SEM) was used to observe and characterize oviposited eggs removed from cotton leaves, artificial membranes, and the morphology of eggs removed from the ovaries of gravid B. argentifolii females. For cotton leaves, the pedicels B. argentifolii eggs were most often inserted into abaxial epidermal cells. We observed that the distal end of most pedicels was curved within the plant epidermal cells. A glue-like substance was observed to envelop the base of the pedicel, but not the tip region. This glue-like collar was also observed on the pedicel of eggs removed from artificial membranes. These findings imply that the female secretes the glue-like substance at the time of egg insertion. SEM observations of eggs removed from ovaries indicate that the pedicels have two distinct morphological areas: The proximal portion as an extension of the smooth-surfaced egg chorion and the distal end appears to be covered with an array of tangled-like fibers. This fibrous appearance at the distal end of the pedicel supports the suggestions and evidence for water uptake into the egg.