|Chu, Chang Chi|
|Freeman, Thomas - NORTHERN CROPS, FARGO, ND|
Submitted to: Sweetpotato Whitefly Progress Review Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 1996
Publication Date: N/A
Technical Abstract: Studies using confocal and bright field light microscopy revealed that feeding structures of 145 attached B. argentifolii nymphs (2nd-4th instar) always reached vascular tissue in cotton and cantaloupe leaves. Analysis of stained and cleared leaves permitted detailed examination of the course of intact feeding structures (salivary sheaths) from the plant's abaxial surface to the target tissue. Nearly every salivary sheath made complex tums and contained several branches that could be considered mistakes in the course of locating target vascular bundles. Only minor vascular bundles were found to be the targets of the whitefly nymphs. The position of minor vascular bundles were invariably associated with elongated surface cells. Although they were in contact with or close to elongated epidennal cells, all attached nymphs made mistakes in their progress towards the target bundles. Confocal microscopy revealed that the specific targets within the vascular bundles were apparently always phloem cells. This technique also showed that the sheaths often wrapped around spongy parenchyma cells on their course to vascular bundles. Once within the bundle, the sheaths often wrapped around the xylem elements and seemed always to terminate in phloem elements. Very often a single sheath that reached a minor vein would branch at the bundle into at least two and as many as six salivary sheaths.