[5] The symptoms of both forms of P. teres are similar in that they begin with pin-sized brown necrotic spots on the lamia and sheath of the leaves (the most common infection court), and sometimes on the flowers and grains.

[4][6] Barley plants infected by P. teres f. maculata, causal agent of the spot form of net blotch,[7] do not exhibit net-like patterns of necrosis.

These appear as dark, 1–2 mm spherical structures with septate setae on the surface of plant debris, which, during cool and moist conditions, mature and produce ascospores that are dispersed by wind and rain, thereby colonizing the leaves of new barley hosts.

The severity of the pathogen's spread relies heavily upon certain environmental factors, as the conidia require specific temperature (10-25 degrees Celsius),[6] relative humidity (95-100%), and leaf wetness for dispersal and germination.

[4] As long as the environmental conditions are suitable many secondary disease cycles can occur, resulting in potentially devastating infection rates if the cultivated barley is of a susceptible variety.

[6][4] Pseudothecia are formed by mycelia in necrotic tissue at the end of the season in order to facilitate overseason survival and the re-initiation of the disease cycle when conditions are once again favorable.

[4] An integrated approach is suggested due to the occurrence of frequent genetic recombination, which can quickly make some fungicides obsolete, and cause previously resistant barley cultivars in a region to succumb.

[6] Cultural management practices generally work to reduce the primary inoculum source (the pseudothecia) present in barley stubble[4] through destruction the residual debris and through crop rotation.

Good crop nutrition to promote healthy plants that are more resistant to disease and delayed sowing can also be used to bolster the effects of other management practices, but these are not adequate enough to be used as the sole means of control.

[4] During plant-fungal interactions involving Pyrenophora, resistant and susceptible varieties of barley display differential levels of reactive oxygen species production.