SCIMAT / SCIENCE PHOTO LIBRARY SCIMAT / SCIENCE PHOTO LIBRARY
Cedar-hawthorn rust caused by a fungal pathogen, Gymnosporangium globosum. This disease occurs on eastern red cedar, Rocky Mountain juniper, southern red cedar, common and prostrate junipers, apple and crabapple, most hawthorns, and sometimes on pear, quince, and serviceberry. To survive, the fungus must move from one type of host to another. On deciduous hosts, small yellow spots first appear after infection in the spring. As the spots mature and enlarge, they take on an orange color and develop tiny black dots (spermagonia) in the center of the lesion. By mid-summer, tubes (aecia) are visible on the undersides of mature leaf lesions or within the lesions on fruit, petioles, or twigs infections.
Model release not required. Property release not required.