b'North Dakota Certified Seed Potatoes 2020 Crop Winter Grow Out ResultsBy Kent Sather, North Dakota State Seed Department, Potato Program DirectorA priority of a winter test grow-out Dakota. passing summer inspections. Basedfor certified seed potatoes is estimat- onNorthDakotaswintertestdis-ing virus levels of the harvested seed 2020cropcertifiedseedlotswere easetolerances,samplelotsrepre-instorage.Lateseasonspreadof sampledbyNorthDakotaseed senting 5,985 acres were deemed eli-PVY (Mosaic) can result in asympto- growersatharvesttime,compiled gible for recertification in 2021. Thematic infections of this virus. PVY byNDSSDstaff,shippedtoAlger onlyfactorcausingineligibilityofinoculumresidingincommercial Farms,Inc.atHomestead,FLand the remaining 1,426 acres was PVYfields is easily vectored by aphids to planted by NDSSD staff November incidencegreaterthanthe0.5%nearbycertifiedseedfields. 17-20, 2020. Inspectors returned to virus tolerance.Nonspecificaphidflightsfrom the plots for visual readings Januarymaturing grain crops and soybeans 2-18,2021.Leavesfromsomelots Table 1 shows a historical compari-also contribute to this virus spread. were also lab tested by staff in Fargo. sonofacresrepresented,eligible,SincePVYiseasilytransmittedby Results of readings are crucial to the andzero(0)PVYpercentagesaphidsanytimeduringsummer grower, and the industry, since they recordedatthewintertest.Thesegrowth, there may be an increased determineseedlotseligibleforre- are all significantly better for 2020level of PVY in harvested tubers.certification in 2021. than the previous years. More acresareestimatedtobePVYfreethanSummer inspections and leaf testing Recertificationeligibilitydepends past years. Less PVY spread occurredby trained North Dakota State Seed ontolerancelimitationsstatedin in 2020 than in 2019. Department(NDSSD)personnel North Dakota rules and regulationsprovides information on how much for certification of seed potatoes. No An electronic version of the Northviruswasplanted.Wintertest morethan0.5%virus,including DakotaApprovedSeedListforresults indicate how much virus was PVY, is allowed in a seed lot to be Recertificationbasedonthe2020harvested.PVYisayieldlimiting planted for recertification. crop winter test inspections can bevirus and therefore has a tolerance foundatwww.seed.nd.govunderrestriction in certified seed. It is the North Dakota certified seed growers the Directories tab.primary pathogen causing rejection submitted 345 seed lots, represent-of certified seed potatoes in North ing 7,411 acres of the 14,624 acresTable 1 Total Acres% EligibleAcres Crop Year Represented Eligible Acres Acres 0 PVY % 0 PVY 20168,338 6,797 824,881 5820178,000 5,711 713,721 4720188,045 5,545 692,834 3520196,883 4,055 591,704 2520207,411 5,985 813,439 46 ARCH 2021 POTATO GROWER 15M'