New strain of potato virus Y has industry’s attention

A potato virus that has been around for years is mutating and that’s got both researchers and industry leaders worried.

Growers have grown used to seeing some signs of Potato Virus Y, better known as simply PVY, in fields. The disease causes foliar damage and infected plants must be rouged out of certified seed fields, but otherwise the virus hasn’t really been a threat.

But that could be changing. Researchers are finding new strains of the virus that damage tubers with little apparent injury to an infected plant’s leaves. When potato specialists in the U.S. surveyed PVY strains between 2004 and 2006, they found 70 percent of the identified strains were the ordinary PVY that causes leaf damage but not tuber damage.

But by 2010, surveys showed tuber necrotic strains are increasing in both incidence and distribution, said Stewart Gray, a plant pathologist with the Agricultural Research Service in New York. Tuber necrotic strains accounted for 18 percent, up from 6 percent previously, and ordinary strains had fallen to 53 percent.

“This is no longer just a seed certification problem,” Gray told potato growers during the University of Idaho Extension Potato Conference last week. “The problem now affects all aspects of potato production.”