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Disease Management

Cultural Practices

Because ergots (sclerotia) do not usually survive for more than one year, rotation with a non-susceptible host plant is a viable management tactic for annual crops. Deep plowing buries sclerotia, so ascospores from stromata cannot be discharged into the air. Although deep plowing buries the ergots, many cereal crops are now grown with "no-till" practices in which new crops are seeded directly into the stubble from the previous crop to reduce soil erosion. Crop rotation is even more important when deep-plowing is no longer an option.

Ergot is one of the most important diseases in grass seed production. Because many of the grass species are perennial, tillage and crop rotation are not management options. Post-harvest field burning has been practiced in the northwestern U.S. to manage ergot and other diseases and pests since the 1940s, but environmental concerns have resulted in legislative restrictions to burning.

Only ergot-free seed should be planted. If seed containing ergot is planted, it should be planted at least 5 cm (2 in) deep to prevent emergence of the stromata. Wild grasses along fence rows should be eradicated or mown or grazed to prevent flowering (Figure 8).

Figure 8

Chemical Control

Chemicals have been applied to seed or soil to inhibit production of ascospsores from sclerotia, but are not economical. Recently, sterol-inhibiting fungicides have been applied to flowers to prevent infection in grass seed production, but such treatments are not usually economical in cereal production.

Genetic Resistance

Interest in genetic resistance to ergot has increased since the 1970s with the creation of male-sterile lines of wheat and barley for hybrid seed production. Wheat and barley are self-pollinated plants, unlike rye which is cross-pollinated. Effective male-sterility systems provide the opportunity for hybrid seed production, however, male-sterile plants flower longer and remain susceptible until they are fertilized. Fungicides may be necessary to protect them from infection.

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