UNIVERSITY PARK, Pa. – A section of sidewalk on the Pugh Street Mall near the Biobehavioral Health Building, and another section of walkway on Pattee Mall near Carnegie Building, will be closed on July 21 and 25, respectively, to allow University arborists to remove two elm trees suffering from elm yellows disease.
Pedestrian traffic will be routed around the work areas on each day until the trees’ removal is complete.
Elm yellows, also known as elm phloem necrosis, is specific to North American elms and is caused by a bacteria-like organism that infects the root cells and the phloem -- the inner bark that carries nutrients to all parts of the tree. The disease essentially prevents the tree from receiving adequate nourishment.
There is no known cure for elm yellows and trees usually die within a year or two from the time they are infected. Elm yellows is spread by insects known as white banded elm leafhoppers.
Efforts to preserve the university’s historic stand of elms have stretched over many years, with targeted care and spraying to combat the spread of elm yellows and Dutch elm disease. These efforts are a part of the university’s tree care plan, which is broadly focused on maintaining a healthy and diverse urban forest on the University Park campus.