|Gerling, Dan - TEL AVIV UNIVERSITY|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 15, 2003
Publication Date: November 1, 2003
Citation: Gelman, D.B., Gerling, D. 2003. Effect of host plant pubescence on the morphology and molting hormone titers of fourth instar/pharate adult silverleaf whiteflies (benisia argentifolii). Meeting Abstract. Vol. # 3 Pg. 25 Technical Abstract: Effect of host plant pubescence on the morphology and molting hormone titers of fourth instar/pharate adult silverleaf whiteflies (Bemisia argentifolii) A system of markers (based on relative body thickness and eye development) that characterizes the development of fourth instar/pharate-adult B. argentifolii was used to track development on pubescent vs. glabrous- leafed plants. When reared on the pubescent leaves of green beans and tomatoes, the period of whitefly development prior to becoming pharate adults could be divided into five stages, with depth (thickness) reaching a maximum of 0.25 to 0.3 mm during stages 4-5. In contrast, when reared on the glabrous leaves of cotton, collard or sweet potato, whitefly body thickness rarely surpassed 0.17 mm, a thickness equivalent to Stage 2. However, whitefly nymphs on glabrous plants were significantly longer and wider than those developing on pubescent leaves. Ecdysteroid titers were significantly higher in stage-2 whiteflies reared on glabrous leaves than in stage-2 whiteflies reared on pubescent leaves; but, in all whitefly plant associations, regardless of leaf pubescence, ecdysteroid titers always peaked in Stage 6 nymphs, either just prior to or at the onset of pharate adult development. Thus, it is apparent that the changes in nymph thickness enabling us to characterize developmental stages 3-5 in nymphs that develop on pubescent leaves, take place within morphological Stage 2 of nymphs that grow on glabrous leaves.