''Phragmidium violaceum'' is a plant pathogen native to

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, and the

Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...

. It primarily infects ''

Rubus ''Rubus'' is a large and diverse genus of flowering plants in the rose family, Rosaceae, subfamily Rosoideae, with over 1,350 species. Raspberries, blackberries, and dewberries are common, widely distributed members of the genus. Most of the ...

'' species. It has been used in the biological control of invasive

blackberry The blackberry is an edible fruit produced by many species in the genus ''Rubus'' in the family Rosaceae, hybrids among these species within the subgenus ''Rubus'', and hybrids between the subgenera ''Rubus'' and ''Idaeobatus''. The taxonomy ...

species in

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

, Australia, and

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

. In 2005, it was discovered growing on

Himalayan blackberry ''Rubus armeniacus'', the Himalayan blackberry or Armenian blackberry, is a species of ''Rubus'' in the blackberry group ''Rubus'' subgenus ''Rubus'' series ''Discolores'' (P.J. Müll.) Focke. It is native to Armenia and Northern Iran, and wide ...

plants in

Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. T ...

. 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 The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Tho ...

Symptoms

CSIRO ScienceImage 3620 Blackberry plants infected with rust fungus

The foliar symptoms that can be found include purple leaf spots along with yellow and tan centers. These can be found on the upper surface of the leaf and can resemble ''

Septoria ''Septoria'' are ascomycete pycnidia-producing fungi that cause numerous leaf spot diseases on field crops, forages and many vegetables including tomatoes which are known to contract '' Septoria musiva'' from nearby cottonwood trees, and is res ...

'' leaf spot. On the lower surface of the leaf yellow to orange pustules will be surrounded by a purple tinge. These can resemble cane and leaf rust. The leaves that are severely infected can start to dehydrate as well as start to curl. The leaves that are older and closer to the cane will get infected first and can die as well. The flowers and the fruits that are infected may fail to ripen. Stem infections as well as the continuous defoliation may cause the dieback of the canes. During the summer and fall the infected leaves can start to develop black pustules otherwise known as telia among the

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