Infections appear as discrete elongated brown spots or lesions. Infections are especially noticeable on the sub-crown internode  (see photo) and coleoptile but are also found on crowns and roots.  When root rot is severe, destruction of root and crown tissue may be so great that plants are killed outright, usually during heading and early filling stages. Plant death may be severe when hot weather follows cool wet weather. Such plants exhibit "early maturity" or "prematurity blight" and the heads frequently appear almost white. When the root rot patches are small (a few yards across) and scattered, they resemble the appearance of salt spots or subsoil sand lenses, with which they are sometimes confused.

In most fields and in most seasons, the symptoms of severe root rot are not present. Fields without obvious symptoms of root rot, dead plants or patches, may still suffer a reduced yield from the disease. Where root rot does not kill, it weakens the plant so that it produces fewer tillers and fewer heads. Grain from root-rotted plants may be shriveled or have a low test weight.

The fungus that causes root rot may also infect above-ground plant parts, causing leaf spot on wheat and spot blotch of barley. If heads are infected, the glumes are discolored by the presence of the fungus. Infection of filling grain also can occur, resulting in "black pointed" kernels.

Crop rotation is probably the single most important tool to reduce root rot. Rotation to a crop other than wheat and barley may lessen the level of C. sativus in the soil, and therefore the level of root rot in the succeeding wheat or barley crops.  The best rotation crops appear to be forage legumes, flax, and hay crops.

Adequate nitrogen and potassium levels appear to reduce the severity of common root rot. However, excessive fertility levels, especially excessive levels of nitrogen, can increase the severity of root rot in wheat and barley.

Seedling vigor plays a role in determining the effect of root rot on the adult plant. Large, heavy seed produces the most vigorous plants and thereby reduces the effects of root/crown rot, even though the amount of spores in the soil is the same. Black-pointed seed infected with C. sativus and scabby seed infected with Fusarium will give reduced stands and weaker plants less able to resist the effects of root/crown rot.

Several seed treatment products are registered for the suppression of common root rot. These include: Imazalil (Agsco Double R, Nuzone and Flo Pro IMZ.), registered for wheat and barley (generally, these products are applied in conjunction with other seed treatment products). Triademefon (Baytan) is also registered for control of common root rot in wheat and barley. Tebuconazole (Raxil) and Difen-oconazole (Dividend) are registered for the suppression of common root rot in wheat only.

Research results have shown these products to significantly reduce common root rot ratings on plants grown from treated vs. nontreated seed. Yield results have been variable, with good yield responses in some cases. The most likely conditions in which seed treatment would be beneficial are: under continuous wheat or barley: where short rotations between susceptible crops occur; and in soils or areas where moisture stress is likely.