|Chu, Chang Chi|
|Natwick, Eric - COOP EXT. HOLTVILLE, CA|
Submitted to: Journal of the Agricultural Association of China
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 1, 2001
Publication Date: December 1, 2001
Citation: Chu, C., Margosan, D.A., Buckner, J.S., Natwick, E., Aung, L.H., Nelson, D.R., Vail, P.V., Henneberry, T.J. 2001. Feeding sites selection and penetration of cotton and cantaloupe leaves by bemisia tabaci biotype b nymphs. Journal of the Agricultural Association of China. 555-568 Interpretive Summary: Using electron microscopes to study feeding behavior of sweetpotato whitefly nymphs, we found that nymphs did not use visible leaf veins as references for the selection of feeding sites and stylet (mouth part) penetration. About 50% of the 88 nymphs settled in the leaf areas that were surrounded by leaf veins. We also found the salivary sheath, the saliva coating the stylet, of feeding nymphs made turns and branched to different directions within leaf tissues before it reached vascular bundles. In some cases, the salivary sheath encircled the xylem tissues before for feeding in the phloem tissues. 1
Technical Abstract: We used stereomicroscope, scanning electron (SEM), bright field (BFM), and confocal laser scanning microscopes (CLSM) to study sweetpotato whitefly (SPW) Bemisia tabaci (Gennadius) biotype B feeding site selection, stylet penetration and phloem tissue location. Nymphs did not appear to use the raised, elongated epidermal cells that overlay leaf veins as cues for selection of feeding sites. Of 88 nymphs examined, 40 were not located over veins, 40 were located over veins 1-3-cells wide and 8 on veins greater than or equal to 4-cells wide, respectively. Minor vascular bundles were not easily visible using a stereomicroscope. Nearly all feeding nymphs produced salivary sheaths within leaf areoles. All salivary sheaths of 45 feeding nymphs (2nd-4th instars) studied reached phloem tissues in cotton and cantaloupe leaves. Most salivary sheaths of feeding nymphs made complex turns and had several branches on their routes to vascular bundles. Once in contact with vascular bundles, the salivary sheaths sometimes encircled the xylem elements before terminating in phloem tissues.