Fargo, ND (AgNews890.com) – NDSU Plant Pathologist Andrew Friskop appeared on Farm Talk with Erick Johnson today and announced that tar spot had been found in North Dakota corn fields for the first time.  Tar spot, a fungal disease that affects corn plants, causes black spots on the leaves, stalks, and husks and reduces yield.  Friskop says that the disease has been found sporadically in 9 southeastern ND counties.