Common root rot is a fungal disease of barley caused by Cochliobolus sativus

Cochliobolus sativus

The fungus Cochliobolus sativus is the teleomorph of Bipolaris sorokiniana which is the causal agent of a wide variety of cereal diseases. The pathogen can infect and cause disease on the root , leaf and stem, and head tissue...

, Fusarium culmorum

Fusarium culmorum

Fusarium culmorum is a plant pathogen and the causal agent of seedling blight, foot rot, ear blight, stalk rot, common root rot and other diseases of cereals, grasses, and a wide variety of monocots and dicots. In coastal dunegrass , F. culmorum is a non-pathogenic symbiont conferring both salt...

and F. graminearum.

Symptoms

Initial symptoms appear as small brown spots on the crown roots, the lower sheath, and the subcrown internode. This spots will elongate and coalesce and can cause an extensive brown discoloration at the crown, and the entire length of the subcrown internode. Healthy root tissue is white to slightly cream-colored.

Disease cycle

In western Canada, infections occur mainly from soil-borne spores, whereas in eastern Canada, seed-borne inoculum is more important. The spores can survive for many years, and germinate in the presence of susceptible plants. At infected plants reach maturity, abundant sporulation occurs.

Management

Disease inoculum is reduced by long rotations with nonhost crops. Shallow seeding and optimum fertilization levels, especially of phosphate and potassium, reduce disease severity. Resistance cultivars are also available.