''Phacidium infestans'' is a fungal

plant pathogen Plant pathology (also phytopathology) is the scientific study of diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomy ...

infecting Douglas-firs commonly known as snow/needle blight.

References

External links

Index Fungorum

USDA ARS Fungal Database
Fungal tree pathogens and diseases Helotiales {{fungus-tree-disease-stub