ABSTRACT

Sweetpotato whitefly (SPW), Bemisia tabaci (Gennadius) crawlers are vulnerable to environmental stress when searching for feeding sites under the extremes of heat conditions in southwest cotton growing area in the summer. Dispersal on plants may be a limiting factor in population dynamics in the field. We examined dispersal behavior differences on field grown cotton leaves in the laboratory in 1999 and 2000. Three out five crawlers released on lower leaf surfaces remained at the origin of releases, but all six crawlers released on upper leaf surfaces moved away from the release point origin. Compared with lower leaf surfaces, crawlers released on upper leaf surfaces stopped 7X more often but spent 70% less time per stop. They changed directions 7X more often and took 2X longer to travel 1.0 mm distance compared with crawlers released on lower leaf surfaces.