OVIPOSITION PREFERENCE OF 2 BEMISIA SPECIES (HOMOPTERA, ALEYRODIDAE)

Adult females of the silverleaf whitefly, Bemisia argentifolii Bellows & Perring, and the sweetpotato whitefly, B. tabaci (Gennadius), were given access to three different host plants in choice and no-choice experiments to determine if oviposition preference could account for field observations of host use. The experimental host plants were zucchini, which is a preferred host for both species; sugar beet, which is not favored by either species; and cabbage, which is preferred by B. argentifolii and rarely used by B. tabaci. In choice trials, both whitefly species laid the greatest proportion of eggs on zucchini. The lowest proportion of eggs laid by B. argentifolii was on sugar beet, whereas B. tabaci laid its lowest proportion on cabbage. The proportion of eggs laid on cabbage by B. argentifolii was significantly greater than that laid by B. tabaci. In bihourly counts, females of both whitefly species were found on each host in approximate proportion to their oviposition choice. In no-choice trials both whitefly species laid approximately the same numbers of eggs on zucchini; yet on cabbage and sugar beet, B. argentifolii laid significantly more eggs. An additional experiment revealed that B. tabaci would oviposit on cabbage to the same degree as B. argentifolii if the leaf surface was rubbed smooth.