Bunt can be difficult to detect as it is inconspicuous in the standing crop until near maturity. Infected plants are moderately stunted and produce fewer, smaller heads than normal plants. In infected heads, gray-brown bunt balls filled with dark brown spores replace all or some of the kernels. Crushing a bunt ball releases a foul, fishy odour.
Common bunt reduces yield and quality. Yield losses are equivalent to the percentage of infected tillers. Grain contaminated with bunt balls is discounted at the elevator.