U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska


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Agricultural Research Magazine 60(2): February 2012 pp. 8-9; ISSN 0002-161X


Thanks to the investigations of scientiststurned- detectives, potato growers in the western United States and abroad now know the identities of the pathogen and insect responsible for outbreaks of the costly tuber disease known as “zebra chip.”

So named for the dark stripes it forms inside afflicted tubers when cut and fried to make chips or cooked at high temperatures for other dishes, zebra chip has caused millions of dollars in production and processing losses since its first reported U.S. occurrence in potato fields near McAllen and Pearsall, Texas, in 2000. The disease, whose above-ground symptoms include necrosis and purplish, upward-curling leaves, among others, has since been reported in several other states (California, Nevada, Kansas, Nebraska, New Mexico, Colorado, Wyoming, Washington, Oregon, and Idaho), Mexico, parts of Central America, and New Zealand.

Intensive collaborative research by university, industry, and government scientists, including teams from three ARS laboratories—the Yakima Agricultural Research Laboratory (YARL) in Wapato, Washington; the Vegetable and Forage Crops Research Laboratory (VFCRL) in Prosser, Washington; and the Beneficial Insects Research Unit (BIRU) in Weslaco, Texas—narrowed the list of likely suspects to a fastidious (nonculturable) bacterium, Candidatus Liberibacter solanacearum, and the potato psyllid, Bactericera cockerelli, as its insect accomplice or “vector.” (See “Bacterium Identified as Prime Suspect in Zebra Chip Case,” Agricultural Research, October 2009, p. 22.)