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The causal agent of eyespot is a fungus that attacks cereals and grasses. The pathogen causes brownish discoloration, medallion spots, bending of the stalks and death of the ears.

Host plants

The eyespot disease affects all cereals, with the winter forms of wheat and triticale most at risk. Other host plants include a number of cultivated and wild grasses.

Two strains (pathotypes) can be distinguished in eyespot. The W-type(Tapesia yallundae): almost exclusively attacks wheat, the R-type(Tapesia acuformis) is found on all cereals to the same extent.

Distribution

The eyespot disease occurs in all countries where cereals are grown. In Austria, the disease is also widespread, especially in mild winter and wet spring weather. Cereal-intensive crop rotations in cereal-growing areas have a promoting effect on infestation.

Propagation and transmission

The disease is favored by mild winters and cool, damp weather conditions in spring. Infection usually starts from the crop residues in the soil, in which the fungus can survive for at least two years. Rain splash disperses the fungal spores over small areas in the stand and they enter the tissue through dying cotyledon sheaths (coleoptiles) or leaf sheaths. From this entry point, the fungus continues to grow into the culm and begins to destroy the culm tissue. The optimal conditions for infection are mainly late fall and early spring, when high humidity and temperatures between 5 °C -10 °C prevail.

Economic importance

As the proportion of cereals in the crop rotation increases, eyespot becomes more important. It is thus a crop rotation disease that is of great economic importance, especially in cool, wet growing years.

Prevention and control

• Crop rotation planning is one of the most important preventive measures to minimize the risk of infestation. Tight cereal rotations, especially with a high proportion of wheat and cereals (triticale), increase the risk considerably.
• Other crop management measures include selecting low-susceptible varieties and eliminating volunteer cereals by stubble cultivation.
• Chemical or biological control of eyespot: targeted control by fungicides (see list of plant protection products approved in Austria) is possible, but at the optimal time of spraying(BBCH32) the symptoms of the infestation are hardly visible.

Specialized information

A forecast model for eyespot in winter wheat and winter barley is offered on thewarning service page of the Chambers of Agriculture. With these warnings, a possible infestation in the individual regions can be better assessed.

Services

Plant Health Services