Cause The fungus Colletotrichum gloeosporioides has been found a few times by the OSU Plant Clinic. Young juvenile tissue is susceptible to infection while older mature leaves are resistant. A problem during unusually high rainfall years.
Symptoms Brown necrotic leaf blight as well as black leaf blights and twig dieback of new shoots.
Cultural control Not needed in natural settings as trees shed leaves and recover.
Reference Parmeter, J., Bega, R.V., and Hood, J.R. 1960. Epidemic leaf-blighting of Californian-Laurel. Plant Disease Reporter, 44:669-671.