Epidemiology of Gremmeniella abietina and G. laricina During the Past 35 Years in Austria : Shoot and Foliage Diseases in Forest Trees. Proceedings of a Joint Meeting of the Working Parties Canker and Shoot Blight of Conifers (S2.06.02) Foliage Diseases (S2.06.04)

Florenz

1995

S. 204-209

6 Lit. Ang.

Bandaufführung

77412

Epidemics of both fungi became obvious in 1967 on all afforestations on subalpine sites, first at higher elevations (2.000-2.300 meters), but soon also on lower ones. The development of mortality was observed by numerous marked plants on different sites over many years. Mortality of Pinus cembra and Larix europaea reached 100 on many sites. Most serious losses occurred until the late 1970ies and decreased gradually; since the late 1980ies both epidemics slowed down considerably. During the past years one hardly could find Pycnidia of Gremmeniella laricina and those of Gremmeniella abietina are not very common, either. During the years of epidemic occurrence it was easy to observe abundant apothecia formation (on perennial cankers). At present, it seems to be impossible to find apothecia. Long-lasting observations gave results on site influences and on the problem of suitable provenances. Studies on the genetics (of Gremmeniella abietina) proved that there was no introduced strain involved. Possible causes of the epidemics and the lessons from the experiences for inoculation experiments and some early conclusions will be discussed.