European Pear Rust

Gymnosporangium sabinae

European Pear Rust is triggered by the fungus Gymnosporangium sabinae and is frequently observed on pear trees and various other cultivars in September. An orange-yellow patch appears on both sides of the leaf when a gall develops. The galls often resemble cow udders. This fungus requires two distinct host plants to complete its annual life cycle. Spores are released from the tips of the udders to locate juniper, which serves as the winter host and affects the stems.