|Freeman, Thomas - NORTH DAKOTA STATE UNIV|
|Chu, Chang Chi|
Submitted to: National Research and Action Plan for Silver Leaf Whitefly
Publication Type: Abstract Only
Publication Acceptance Date: December 20, 1999
Publication Date: N/A
Technical Abstract: Using light and electron microscopy we have determined that the adult Bemisia argentifolii Bellows & Perring (Homoptera: Aleyrodidae) stylet lengths are considerably longer than have been previously reported. Adult whitefly stylets range from 100 um to over 300 um in length. Stylet penetration was determined by rapidly killing and fixing feeding silverleaf whiteflies in acidified DMP (2,2-dimethoxypropane) and then removing them from the leaves and measuring the stylet extended beyond the distal tip of the labium. The portion of the stylet extended into the leaf ranged from 43 um to over 150 um with a mean penetration of 90 um. Using the same technique to kill and fix nymphs feeding on leaves we found their stylets to also be considerably longer than previously reported. Stylet lengths were found to be shorter in crawlers than in 4th instar nymphs. Crawler stylets measured as long as 113 um whereas some 4th instar nymphs had stylets over 200 um long. With stylets of these lengths and the arrangement of minor veins in cotton leaves, both adults and nymphs may be able to reach phloem tissue from almost any point on the abaxial epidermis of the youngest expanding leaves or even leaves located at nodes 7-15 below the apex. Thus, stylet length and phloem depth may not be a determining factor in successful whitefly feeding.