Yellow Fungus (Phragmidium) on Wild Rose and other Plants

Observation: I have never seen or at least noticed this yellow / orange fungus on plants in this area. I was hiking along Johnson Trail south of Anchorage and saw this on a dozens of plants all along the trail. Rose bushes mostly. I am interested in identifying it and wondering whether the early, warm weather conditions this summer might be a factor.

Cooperative Extension Service Consult: Jessie Moan, Statewide IPM Technician writes, "This is rose rust in the genus Phragmidium. There are several species of this fungus in Alaska and we see them fairly regularly. Some years are better for the fungus than others, weather wise. There are other rust fungi that will infect other plants, another common one can be found on willow leaves. We have seen a lot of rose rust this year and last year." University of Alaska Fairbanks

LEO says: The yellow fungus observed on the wild rose has the characteristics or resemblance to the rust fungus (Phragmidium). This post has been forwarded to our partners at UAF's, Cooperative Extension Service for further identification. (M. Tcheripanoff)