Emerald ash borer has been discovered in another Minnesota County. The Minnesota Department of Agriculture says EAB has been discovered in Itasca County for the first time. The agriculture department says a homeowner on Pokegama Lake south of Grand Rapids reported the infestation. It was confirmed by a Minnesota DNR health specialist. There are now 59 Minnesota counties with EAB after first being discovered in 2009. The insect larvae kill ash trees by tunneling under the bark and feeding on the part of the tree that carries nutrients up and down the trunk.