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Publisher Summary Bemisia tabaci Gennadius has been widely recorded on many plant hosts throughout the zone between latitudes 40° North and 40° South around the world. Bemisia argentifolii has been recorded from over 900 plant species in 74 families [4, 5]. Outbreaks of B . argentifolii in Arizona, California, Florida, and Texas caused estimated crop losses in excess of $500 million in 1992. Bemisia tabaci s. 1 is resistant to most insecticides and, despite massive pesticide spraying, its numbers continue to increase. The history of the occurrence, distribution, and severity of B. argentifolii, the silverleaf whitefly (SLWF), in the United States is a curious but salutary one. The circumstances leading to the outbreaks are unknown but are probably related to the use of extensive pesticide applications, which reduced natural controls and enhanced resistance to chemical products. After its accidental introduction, SLWF became adapted to cole crops in the agricultural region of southern California and was recognized as a problem when several visible disorders of cruciferous crops appeared at the same time. A number of physiological disorders leading to weight loss of cole crops have been associated with the presence of immature whitefly stages: in Hawaii, yellowing and stem blanch in kai choy and in 1990 in Arizona, white streaking disorder of broccoli and cauliflower. |
