A potato disease that arrived late this summer in the US Pacific Northwest called zebra chip likely can’t be spread by planting infected seed, new research suggests.

Joseph Munyaneza, a research entomologist with USDA ARS Yakima Agricultural Research Laboratory Washington, said countries including New Zealand and Mexico have voiced concerns that the disease could be spread through seed, reported Capital Press.

“If a country says, ‘We don’t want your seed because you’re going to contaminate our country,’ this is something to use,” Munyaneza told seed growers gathered Tuesday at the Seed Potato Growers Seminar hosted at the Clarion Inn. “I don’t think any country should deny you to export your potatoes because they’re afraid of getting zebra chip.”

Zebra chip is named for the dark stripes that show up during frying of infected tubers. Symptoms, including curled, pinkish leaves, surface three weeks after infection. It effectively stops tuber development and makes potatoes unmarketable.