Submitted to: National Research and Action Plan for Silver Leaf Whitefly
Publication Type: Abstract Only
Publication Acceptance Date: December 17, 1997
Publication Date: N/A
Technical Abstract: Bemisia argentifolii is generally found on the lower surface of most host plants, but from about 1% to over 60% of the immature population may be found on the upper surface. Most studies have been conducted on Bemisia on the abaxial leaf surface. However, it would be useful to know the fate of those that occur on the adaxial leaf surface. A study was conducted to determine any influence of leaf surface on immature survival and adult body size of B. argentifolii, and determine the likelihood of movement by the crawler from the adaxial leaf surface on selected vegetable hosts. Laboratory tests were conducted on cantaloupe, collard, cowpea, bell pepper, and tomato. On the upper surface, survival to the first stadium was high (85-95%) on all crops. Movement of the crawlers from the upper to the lower surface was high on pepper (ca. 80%), cantaloupe (ca. 55%), and cowpea (ca. 55%). Conversely, less movement to the lower surface was observed on collard (ca. 18%) and tomato (ca. 30%). Only a small negative response to light by the crawler was detected. Thus, the impetus to move is apparently a response to feeding and tactile cues. Survival was similar between whitefly nymphs on the upper and lower leaf surfaces for each crop, except significantly more survived on the lower surface of cowpea compared with the upper surface. Data are still being collected on adult body size.