Description:Tan to brown (occasionally silver) irregularly shaped blotches with thin yellow rims on the leaves in late winter to spring. The blotches may run along the veins sometimes and have straight sides. There are usually black specks or fruiting bodies within the blotch especially later in the season.
Species Affected:Wheat, Cereal Rye.
Biology:More common on early sown crops.
Life Cycle:The fungus survives summer on wheat stubble and after the first autumn rains produces large quantities of spores that are spread large distance by wind. These spores infect emerging crops and early sown crops are at greatest risk. 3-4 weeks infections fruiting bodies appear on leaves and again produce large numbers of spores that are spread from leaf to leaf within the crop by rain drop splash. Frequent, heavy rainfall at this time increases the spread and severity of the disease. Dry periods of 3-4 weeks in winter and spring can arrest the spread of disease.
Origin and History:Distribution:
Significance:30% yield loss in wheat can occur in seasons favourable to the disease.
Management and Control:Sow resistant varieties. See Disease Susceptibility of Wheat Varieties. This reduces the effect on the current crop and reduces inoculum levels for future crops.
Related and Similar Species:Septoria Nodorum Blotch of Wheat (Phaeosphaeria nodorum)