Septoria leaf spot (Septoria tritici)

Septoria leaf spot: biology

Also known as Septoria leaf blotch, this disease is caused by Septoria tritici. The fungal pathogens overwinter on crop residue and produce two spore types. One is dispersed short distances by rain splash and the other is dispersed long distances by wind. Wet warm weather favors the disease. The disease can also be seed-borne.

Initially small yellow to brown flecks occur on leaves. These expand to irregular yellow to brown lesions sometimes with grey to brown centers and yellow edges. Small black dots, sporulating structures of the pathogen, appear in the diseased areas and distinguish this leaf disease from others. S. nodorum also causes glume blotch on wheat and barley. Septoria leaf blotch/spot causes shrivelled seed and reduced seed set which lowers yield.