Larry Hawkins, a spokesman for the U.S. Department of Agriculture, says the discovery of the potato cyst nematode in an eighth field won't cause potatoes from Idaho to be banned by some nations.
That's what happened when the nematodes were first discovered in 2006.
The latest discovery confirmed last week is in a field adjacent to two fields already infected, and Hawkins says the find is not surprising.
Earlier this year, Canada and Mexico lifted their bans of all fresh potato imports from Idaho.
Japan still bans fresh potatoes from Idaho, but accepts them from other U.S. states.
Officials are trying to kill the nematodes in the infected Idaho fields by covering the ground with tarps and then fumigating.