The symptoms caused by Teratosphearia epicoccoides vary depending on the host species and stage of development of the infection. Infection is usually found on older foliage or on the foliage of stressed trees. (Andjic et al., 2019). In Eucalyptus, symptoms of T. epicoccoides infection initially appear as small purple angular leaf spots that are obvious on the top surface of the leaf. These spots then expand and coalesce, eventually covering the entire leaf surface. On the underside of the leaf, lesions turn yellow to yellow-brown and form angular blotches that are defined by leaf veins. A ‘charcoal’ appearance may be observed due to the covering of the underside of the leaf by brown to black spores (Carnegie, 2008; Walker et al., 1992).

Teratosphearia epicoccoides infects leaves by penetrating through stomatal pores. This has been observed to occur within 48 hours after inoculation. Spore production occurs on the underside of the leaves where the spore-producing structures form within stomatal cavities (Solis et al. 2021).

Breeding and selection for tolerance against T. epicoccoides is possible but due to it being considered as a weak pathogen, research in management has not been extensively researched.