This pathogen usually affects trees that have already been weakened as a result of stressful factors, such as drought or fungal infestation.
The pathogen forms pink fungal blobs (indicative of its sexual stage) on the outside of dead wood which turn a reddish-brown color and become quite hard.
[1] The pathogen thrives in dead wood and airborne spores infect living trees and shrubs through wounds.
Since it is caused by a weak fungus, isolation of the pathogen from diseased tissue and an analysis for fungal properties, such as induced sporulation or microscopically seeing cross-walls in hyphae, can aid in diagnosis.
[6] Furthermore, many fungi studies in media involve the formation of concentric hyphal zonations or rings of sporulation as the colony develops.
During spring or early summer, coral pink or light purplish red spore-producing structures form.
This is the asexual stage and it is characterized by spongy conidia which can be distinguished by the hard, dark red blobs on the bark.
Pruning should be done during dry periods to prevent the possibility of creating a wound in the tree while the fungus is sporulating.
Choosing tree species that grow well in the environmental conditions of the area is a good way to keep them from being stressed.
[9] The pathogen was first described in 1791 when the German mycologist and theologian Heinrich Julius Tode described this fungus under the scientific name, Sphaeria cinnabarina.
This name was changed when Swedish mycologist Elias Magnus Fries transferred the species to the Nectria genus in 1849.
It is also possible for the spores of the pathogen to infect living tissue through the lenticels, but this typically only occurs in stressed plants.