BOISE, Idaho – An eighth field in Idaho has been found to be infected with a microscopic wormlike pest that attacks potato plants, though officials don’t expect the same fallout U.S. growers suffered last year.

The latest southeastern field infected with the potato cyst nematode is adjacent to two others already infected, officials said Tuesday. It is the eighth detected in Idaho since 2006.

After the nematodes were first discovered last year, Japan banned all fresh U.S. potato imports, and Canada and Mexico banned all fresh potato imports from Idaho.

Earlier this year, Canada and Mexico lifted their bans. Japan still bans fresh potatoes from Idaho, but accepts them from other U.S. states.

Larry Hawkins, a spokesman for the U.S. Department of Agriculture based in Sacramento, Calif., said he didn’t anticipate repercussions from the latest infestation.

The worms feed at the roots of potato plants and can reduce crop production by 80 percent. Officials say the pest is not harmful to humans and doesn’t have any effect on the potatoes themselves.