Septoria leaf blotch fungus survives on wheat residue on or near the soil surface. Initial symptoms appear as chlorotic flecks on seedling leaves in contact with the soil. Foliar infection results from sporulation that occurs in the fall or spring during prolong wet periods and temperatures of 59 to 68 F. Lesions initially appear as light green water-soaked areas. Lesions expand into yellow to reddish brown patches with parallel margins restricted by leaf veins. Lesions will continue to expand under favorable moisture and temperature conditions, and can destroy entire leaf area. Septoria leaf blotch also attacks leaf sheaths, stem tissue and occasionally head tissue. Dark fruiting bodies (pycnidia) appear as brown-black flecks scattered within the lesions. Spores from pycnidia are spread by splashing rain. Favored by heavy nitrogen fertilization and dense foliage.