Spores of common bunt infesting wheat seed germinate in the soil at temperatures of 40 to 60 F and infect germinating seedlings before emergence. Kernels of bunted heads are replaced with darkened sori or bunt balls containing black spores with a characteristic fishy odor. Infected plants may be somewhat stunted, but often are difficult to identify before heading. Both healthy and diseased heads can occur on the same plant, and both healthy and diseased kernels can occur in the same head. 'Smutted' grain is heavily discounted in commercial markets.