Phragmidium violaceum is a plant pathogen native to Europe, Africa, and the Middle East. It primarily infects Rubus species. It has been used in the biological control of invasive blackberry species in Chile, Australia, and New Zealand. In 2005, it was discovered growing on Himalayan blackberry plants in Oregon. This accidental introduction does not appear to be infecting native vegetation, so it offers hope for reducing the impact of invasive blackberries in the Pacific Northwest.