Gymnosporangium libocedri (Henn.) F. Kern 1908

Gymnosporangium libocedri on incense cedar (Calocedrus decurrens)

Gymnosporangium libocedri, the Pacific Coast pear rust, is a plant pathogen and rust fungus.^[1] It produces orange gelatinous growths (telia) on incense cedar in the spring. Its secondary hosts include apple, crabapple, hawthorn, mountain ash, pear, quince, and serviceberry.

'brooming' on Calocedrus decurrens

References

Close up on Calocedrus decurrens