Causal Agent

The fungus Septoria tritici. 

 

Hosts

Wheat 

 

Symptoms

Symptoms of Septoria tritici (leaf) blotch initially appear as tan to brownish colored oval or irregularly shaped lesions on leaves. With time, small dark-brown to black specks appear in these lesions. It is in these specks, which are called pycnidia, that spores of the fungus are produced. Cool (59-68°F), moist conditions favor spread and severity of this disease. 

 

Control

Septoria tritici (leaf) blotch generally is more of a problem in northeastern and east central Oklahoma because of the higher spring rainfall. The fungus survives the summer on infected wheat residue, so destroying the residue after harvest and before planting in the fall greatly helps to limit this disease. Resistant varieties are available; consult the "Wheat Variety Comparisons Chart, 1997," Production Technology - Crops, July, 1997, vol. 9, no. 17 (revised). Fungicides also can be used for control, please contact your local county extension office for current information.