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 ex periments to determine if oviposition preference could account for fie ld observations of host use. The experimental host plants were zucchin i, which is a preferred host for both species; sugar beet, which is no t favored by either species; and cabbage, which is preferred by B. arg entifolii and rarely used by B. tabaci. In choice trials, both whitefl y 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 eg gs laid on cabbage by B. argentifolii was significantly greater than t hat laid by B. tabaci. In bihourly counts, females of both whitefly sp ecies were found on each host in approximate proportion to their ovipo sition choice. In no-choice trials both whitefly species laid approxim ately the same numbers of eggs on zucchini; yet on cabbage and sugar b eet, B. argentifolii laid significantly more eggs. An additional exper iment revealed that B. tabaci would oviposit on cabbage to the same de gree as B. argentifolii if the leaf surface was rubbed smooth.