Some crop damage can be caused by excess nitrogen fertilizer, which increases some root rots and reduces others. Adding nitrogen fertilizer controls Aphanomyces root rot. However, pythium root rot, fusarium and verticillium wilts are encouraged by nitrogen fertilization. Pythius is partially controlled by appropriate nitrogen to phosphorus ratio. Phosphorus fertilization can control seedling and root diseases of cereals.
Phosphates are also beneficial in controlling both fusarium and black rot.
A deficiency of potassium makes the disease more severe due to sugars remaining in old and not transported to new tissues.