disease_substrate_bark
bark
Tryblidiopsis pinastri is associated with death of twigs of Picea abies and other members of the Pinaceae. Studies on living twigs have not yet identified symptoms to predict which twig will die and bear T. pinastri. No strong seasonality has been detected in death of twigs which subsequently bear T. pinastri, though there may be a slight peak in the autumn. In much of southern Sweden the fungus is so abundant that virtually all dead attached twigs subsequently develop fruitbodies of the fungus. During mild winters conidiomata have been observed releasing conidia between January and April; unopened ascomata are often present in September, sometimes as early as August, but do not open until at least early May of the following year. By mid-July most ascomata are opened and some contain empty asci. Exact opening time seems weather dependent. Cultures from dead bark immediately under fruitbodies of T. pinastri yield colonies of T. pinastri whereas brownish, recently dead, inner bark yields colonies of Pezicula livida (Berk. & Broome) Rehm. Tryblidiopsis pinastri fruits on dead shoots peripheral to a living branch, suggesting that it may inhabit living branches or shoots vegetatively and be able to fruit when the particular plant organ dies: many isolations from healthy inner bark of P. abies have yielded T. pinastri (Barklund & Kowalski, pers. comm.). Tryblidiopsis pinastri may thus be an endophyte. As such large areas of trunk bark are at times covered with fruitbodies of T. pinastri it is easy to assume the fungus is involved in the death of the tree. Evidence is, however, no more than circumstantial. The other fungus which grew mainly in the most recently dead material (Pezicula livida) is also a well-known inhabitant of P. abies (Butin & Kowalski, 1990), and is also not thought to be pathogenic. Smerlis (1973) tested the pathogenicity of both T. pinastri (as T. piceae) and P. livida, and concluded that neither fungus was pathogenic to P. abies. Kujala (1950) suggested that a decreased tree vitality may affect the fungal activity
Tryblidiopsis pinastri
Tryblidiopsis pinastri