USA officially declare the absence of Potato spindle tuber pospiviroid in seed potato production
In USA, at a meeting on potato certification held in 1998, it was reported that Potato spindle tuber pospiviroid (PSTVd - EPPO A2 list) had not been detected in seed potato stocks for the last 10 years. Based on this information, fourteen seed potato certification agencies (Alaska, California, Colorado, Idaho, Maine, Michigan, Minnesota, Montana, Nebraska, New York, North Dakota, Oregon, Washington, and Wisconsin) surveyed all seed-potato growing areas for the presence of PSTVd. The survey included general surveillance which involved searching for the occurrence of PSTVd in state seed-potato certification records from 1990 through 2000, and a specific field survey which involved testing selected crops for PSTVd infection by nucleic acid-dot-blot hybridization during 1999-2001. No PSTVd incidents were documented in any of the state certification records, nor was PSTVd detected in the field surveys. Seed-potato certification agencies routinely test seed-potato stocks for PSTVd at a number of certification levels starting with pre-nuclear in tissue culture, continuing with field-increased seed generations during the growing season and ending with post-harvest grow-out plots. Based on these surveys, PSTVd is now considered as absent from all seed-potato growing areas of USA. The situation of PSTVd in USA can be described as follows: Absent from seed-potato stocks, no longer found, confirmed by surveys on seed potato production.
NAPPO Pest Alert
Official Pest Reports - Absence of Potato Spindle Tuber Viroid (PSTVd) in the United States (2004-03-04). http://www.pestalert.org