Submitted to: National Research and Action Plan for Silver Leaf Whitefly
Publication Type: Abstract Only
Publication Acceptance Date: 2/26/1999
Publication Date: N/A
Technical Abstract: The influence of selected horticultural and agronomic plant species on attractiveness for foraging by Encarsia pergandiella Howard was determined. Greenhouse tests were conducted with seven diverse crops: collard, cotton, cowpea, melon, bell pepper, soybean, and tomato. Some of these, such as cantaloupe and cotton, are excellent hosts for Bemisia argentifolii, while others, such as cowpea and bell pepper, are substandard whitefly hosts. The tests were conducted on plants free of whitefly nymphs in an open greenhouse colony of indigenous E. pergandiella. In addition, greenhouse tests were conducted to determine incidence of daily foraging by this parasitoid. The parasitoid was most attracted to cowpea, followed by cotton. The fewest parasitoids were observed on collard. Attractance was based on the abundance of the parasitoids on the plants following their landing on the leaves. Leaf area was similar among plant types. Specific reasons for variable parasitoid foraging among the plant species may include a combination of factors such as plant semiochemicals, plant color, and plant texture. The propensity of the parasitoid to forage on the lower leaf surface compared with the upper surface varied among crops (45-90% was on the lower leaf surface) and over time (50% was on the lower leaf surface around sunrise while, 90% was on the lower surface by mid-day). Overall foraging was low around sunrise and sunset, but peaked near solar noon. Results from this study have implications on parasitoid conservation, and host plant resistance.