Septoria tritici

Septoria tritici is the causal agent of Septoria tritici leaf blotch and occasionally infects other grasses including barley. It is found in all wheat growing areas of the world and is the major disease of wheat in the UK.

The teleomorph is Mycosphaerella graminicola (Fuckel) Schröter

Morphology
Asexual state: Pycnidiospores are hyaline and threadlike and measure 1.7-3.4 x 39-86 μm, with 3 to 7 indistinct septations. Germiniation of pycnidiospores can be lateral or terminal. Cirrhi are milky white to buff. Sometimes in culture nonseptate, hyaline microspores, measuring 1-1.3 x 5-9 μm, occur outside pycnidia by yeastlike budding.

Sexual state: Perithecia are subepidermal, globose, dark brown, and 68-114 μm in diameter. Asci measure 11-14 x 30-40 μm. Ascospores are hyaline, elliptical, and 2.5-4 x 9-16 μm, with two cells of unequal length.