They become grey or greyish-brown and speckled as black tiny fruiting bodies develop. Septoria causes more or less linear or rectangular lesions. There may be dark sporulating structures in the lesions. Note that with tan spot lesions are oval and tan. On the chaff or glumes, brown marks start at the tips, develop downwards and later produce pepper-like black dots.
Infection can also occur on the stems at the joints or nodes.
Scouting Techniques Scout fields prior to flag leaf emergence. If the threshold is met in 3 of the 5 spots sampled in the field, spraying is recommended. If the threshold is met at 1 or 2 of the spots in the field, repeat scouting in about 4 days. You should consider rainfall forecasts as well as scouting information in your decision. Heavy rainfall favours the development of severe disease.