Author
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HENNEBERRY, THOMAS |
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CASTLE, STEVEN |
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Submitted to: Academic Press
Publication Type: Book / Chapter Publication Acceptance Date: 9/1/2001 Publication Date: 10/1/2001 Citation: Henneberry, T.J., Castle, S.J. 2001. Bemisia: pest status, economics, biology, and population dynamics. Academic Press, pp. 247-278. Interpretive Summary: Worldwide issues of sweetpotato whitefly devastations of food and fiber crops stimulated an international conference sponsored by the Rockefeller Foundation, Study and Conference Center, Bellagio, Italy. A brief summary of an invitational address on biology and population dynamics follows. The pest status of sweetpotato whitefly has increased dramatically in numerous crops and countries throughout the world. Damage is caused directly by feeding that reduces plant vigor and yield, by contamination of food and fiber with excreted honeydew, and indirectly by spreading viral diseases. Recent outbreaks in the United States and Mexico, have been attributed to the invasion of an aggressive biotype with a wider range of agricultural and ornamental crop hosts compared to indigenous biotypes. Identification of the new 'B'-biotype was based on 1) a different esterase banding pattern, and 2) induction of squash silverleaf symptoms on infested squash plants. Also, biological and biochemical differences between biotypes occur. Comparison of geographical sweetpotato whitefly populations worldwide has revealed substantial biochemical variation at the enzyme and DNA levels, but its taxonomic significance is uncertain at this time. The pest status characteristics remain consistent even in diverse agroecosytems that vary in climate and crop production. Damaging sweetpotato whitefly infestations are characterized by a progressive buildup on a sequence of crops that accelerate during warm, dry weather. Dispersal within and between crops and high rates of reproduction are vital factors in sweetpotato whitefly population dynamics. Technical Abstract: The pest status of Bemisia tabaci (Gennadius) has increased dramatically in numerous crops and countries throughout the world in recent years. Damage from B. tabaci infestations is caused directly by feeding that reduces plant vigor and yield, by contamination of food and fiber with excreted honeydew, and indirectly by spreading viral diseases. Recent outbreaks in certain regions of the world, notably the United States and Mexico, have been attributed to the invasion of an aggressive biotype capable of colonizing a wider range of agricultural and ornamental crops compared to the indigenous 'A'-biotype. Identification of the new 'B'-biotype was originally based on the following criteria: 1) a different esterase banding pattern revealed in gel electrophoresis, and 2) induction of squash silverleaf symptoms on infested squash (Cucurbita pepo (L.)) plants. Further investigation revealed additional biological and biochemical differences between biotypes that led to the description of B. argentifoli Bellows & Perring, although acceptance of this taxonomic split has not been universal. Comparison of geographical populations of B. tabaci worldwide has revealed substantial biochemical variation at the enzyme and DNA levels, but its taxonomic significance is uncertain at this time. The characteristics that define B. tabaci as a pest, however, remain consistent even in diverse agroecosytems that vary in climate and crop production. Damaging B. tabaci infestations are frequently characterized by a progressive buildup on a sequence of crops that accelerate during warm, dry weather. Dispersal within and between crops and high rates of reproduction are vital factors in the population dynamics of B. tabaci. |
