Zebra chip, which causes discoloration of potatoes, has been confirmed in Idaho just a few weeks after it was confirmed in the Columbia Basin of Washington, according to a news release.

Potato psyllids spread the bacteria-like organism, which is harmless to humans. But it can render the potatoes unmarketable.

The disease causes the way sugar is stored in the tuber. When french fries or potato chips are cooked, the sugar carmelizes, creating dark brown stripes.

The U.S. Department of Agriculture confirmed samples sent in from a processor.

Whether this is a one-year occurrence because of unusual weather or whether the disease is here to stay is unknown, University of Idaho researchers say.

Zebra chip is an annual problem in Texas, Kansas, Nebraska and more recently, Colorado.