​​​Introduction of Cotton leaf roll dwarf-like Polerovirus into the United States: High-Throughput Discovery, Identification, and Genomic Comparisons

September 2019 | 32 min., 59 sec.
by Judith K. Brown
University of Arizona


The purposes of this presentation are to raise awareness about the recent introduction to the United States and the potential risks associated with outbreaks of exotic aphid-transmitted Cotton leaf roll dwarf virus (CLRDV) and to alert the cotton industry of the likelihood that this disease will occur again during the 2019 cotton season in the southeastern United States. Other cotton-growing areas of the country also should be on alert for aphid infestations and possible outbreaks caused by CLRDV. This presentation will provide useful information to help cotton consultants, growers, Extension specialists and agents, breeders, and industry personnel involved in the cotton industry in the southeastern United States recognize Cotton leafroll dwarf virus disease and develop management strategies. Specifically, information is provided about blue disease symptomatology, identification of the suspect causal virus associated with the cotton crop in Alabama in 2017–2018, aphid vector transmission, general information about this polerovirus, and possible current and future management practices. By the end of the presentation, listeners will know about this recent virus introduction to the United States, that it has been identified as a polerovirus most closely related to isolates of CLRDV occurring in Argentina and Brazil (despite its origination in Africa or Asia), and that the disease had been recorded in six southeastern U.S. states by the end of the 2018 growing season. The analysis thus far suggests that the virus is represented by a single genomic type, which is consistent with a “recent exotic introduction” hypothesis. See also the related webcast by Kathy S. Lawrence, “Cotton Blue Disease Caused by Cotton leafroll dwarf like virus: Identification, Symptomology, and Occurrence in Alabama.”​

About the Presenter

Judith K. BrownJudith K. Brown was born in Youngstown, Ohio, and moved at a young age to Scottsdale, Arizona, where she was raised as a “desert girl.” She received her BS from Texas A&M University, her MS from Washington State University, and her PhD from University of Arizona (1984). She was post-doctoral associate and research professor at the University of Arizona until 1999, when she joined the Plant Sciences faculty; she advanced to full professor in 2004. Brown is a world authority on whitefly-transmitted viruses and vector biotypes. She has visited, lectured, and studied emerging diseases in 63 countries and continues to carry out collaborative research in Asia, Africa, and the tropical Americas. She recognized early on that DNA-based methods would transform differentiation of vector haplotypes and viral population studies and applied them concomitantly to explore whitefly and begomovirus diversification globally, developing extensive molecular databases that are still used worldwide.

Contact Information:
Email: jbrown@ag.arizona.edu


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