Septoria Leaf Blotch -Septoria spp
Septoria leaf blotch is particularly damaging to wheat but rarely causes significant losses in barley. Several Septoria species attack all aerial plant parts of wheat and barley throughout the growing season. Initial symptoms of this disease are chlorotic flecks that usually begin on the lowest leaves of healthy plants. Lesions appearing lens-shaped are caused by Septoria nodorum whereas lesions that show parallel borders are caused by Septoria tritici. When no leaf moisture is present, infection sites quickly dry out and develop yellow margins that later turn red brown. Older lesions will develop ashen gray centers with small black specks, which are the pycnidia. The pycnidia harbor spores that disperse with splashing raindrops spreading the disease to healthy plant tissue. These black specks are visible to the eye and serve as a good diagnostic tool. See photo 34.

Photo 34 Lesions caused by Septoria tritici show black pycnidia in centers that can be seen without the use of a hand lens

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