The sweetpotato whitefly (SPWF), Bemisia tabaci (Gennadius), has become a serious problem of a number of agricultural crops in the southern U.S. In the Southwest, SPWF seriously affects summer crops such as melons and cotton as well as fall, winter and spring vegetable crops such as lettuce, broccoli and cauliflower, Since this insect has no dormant overwintering stage, a succession of host plants is necessary to span the gap from cotton season to cotton season. This study characterized seasonal population trends of SPWF in cotton and identified subsequent hosts which were important in the overwintering survival of this insect. The "off-season" hosts include certain weeds as well as cultivated crops; all appear to be important in the seasonal population dynamics of this species.