They must first land on flowers, fallen petals, and pollen on the stems and leaves. These provide the food necessary for the spores to germinate, grow, and infect the canola plant. The symptoms usually develop several weeks after flowering begins. The plants develop pale-grey to white lesions, at or above the soil line and on upper branches and pods. The infections often develop where the leaf and the stem join because the infected petals lodge there.
Infected stems appear bleached and tend to shred.
Hard black fungal bodies, of varying sizes, develop within the infected stems, branches, or pods. Plants with girdled stems wilt and ripen prematurely. The symptoms include premature ripening and pale-grey or white lesions on stems, branches and pods. Sclerotia form within the stems, branches and pods. Severely infected crops frequently lodge, shatter at swathing, and make swathing more time consuming.