 It is more likely to occur when seed is sown into cold, wet soil, the pH of the soil is too low, or the roots have already been damaged by carrot fly larvae.Several fungi are associated with canker, including "Phoma complanata", "Ilyonectria radicicola", "Itersonilia pastinaceae", and "I. perplexans".In Europe, "Mycocentrospora acerina" has been found to cause a black rot that kills the plant early.