Seed Certification and PVY

Wisconsin Seed Potato Certification Program

Healthy seed potatoes are the key to success for potato growers and seed potato certification helps growers raise a profitable crop.

Since 1913, the Wisconsin Seed Potato Certification Program (WSPCP) has inspected and certified Wisconsin seed potatoes. The WSPCP, which is in the UW-Madison Department of Plant Pathology, started as a collaboration between farmers and UW faculty. Both the Wisconsin Seed Potato Improvement Association and the Wisconsin Department of Agriculture and Consumer Protection also provide program oversight.

Our goal is to provide potato farmers with high-quality, clean early generation seed potato planting stock  without varietal mixture. We do this through field inspections, diagnostic laboratory services, and minituber production of the seed potato crop along with the valued expertise of Wisconsin seed potato growers. Early generation seed potato stocks produced in our potato tissue culture laboratory, nuclear greenhouses, and at the Lelah Starks Elite Foundation Seed Potato Farm aid in this endeavor by providing Wisconsin farmers with a reliable source of healthy seed potatoes.

Potato Virus Y

Potato virus Y (PVY) is an aphid-transmitted virus that causes disease in numerous solanaceous crops including tomato, pepper, tobacco, and potato. In potato, PVY can be a yield-limiting pathogen that can cause yield loss in heavily infected commercial lots and in selected, susceptible varieties. The virus may also cause post-harvest losses due to tuber necrosis and reduced storage quality. PVY has been managed in Wisconsin for decades, but in recent years it has re-emerged as a potentially serious disease problem. The emergence of new genetic recombinant strains of PVY that can cause mild disease symptoms, the over-wintering of potato-colonizing aphid species (green peach aphid, potato aphid), and the widespread adoption of potato varieties that express mild symptoms of PVY infection are all thought to contribute to the re-emergence of PVY in Wisconsin.

Both commercial and seed potato growers are at risk of direct yield loss due to PVY infection when levels exceed established tolerances. Commercial growers of fresh-market, processing, and chip potatoes are at risk of reduced yield and tuber storage quality if PVY-infected seed pieces are planted. Seed growers are at risk of having their lots downgraded or even rejected from certification due to PVY infection. (allowable tolerances for PVY infection in Wisconsin seed lots are 0.5 percent infected seed pieces for ‘Foundation’ class and 5.0 percent for ‘Certified’ class: Wisconsin ATCP 156).