Barley net blotch

Net blotch is named for the netlike symptoms produced on barley leaves. On adult plants, narrow, dark brown, longitudinal and transverse striations appear, forming the characteristic netlike pattern. Severely infected leaves may become completely necrotic and dry up. P. teres exists in two forms: P. teres f. teres, which causes the net type symptom on barley leaves, and P. teres f. maculate, which causes the spot type symptom. Spot type symptoms are characterized by dark brown, circular to elliptical (3 x 6 mm) spots, surrounded by a chlorotic zone of varying width. The development of different lesion types depends on the barley genotype and the isolate of the pathogen. In addition to the leaves, P. teres can also affect kernels, leaf sheaths and stems of barley plants.