ARS | Publication request: FIRST REPORT OF PHRAGMIDIUM VIOLACEUM INFECTING HIMALYA AND EVERGREEN BLACKBERRIES IN NORTH AMERICA

Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 16, 2005
Publication Date: September 16, 2005
Citation: Osterbauer, N., Trippe, A., French, K., McKemy, J., Bruckart, W.L., Peerbolt, T., Kaufman, D., Aime, M.C. 2005. First report of Phragmidium violaceum infecting Himalya and evergreen blackberries in North America. Plant Health Progress. Online. Plant Health Progress doi:10.1094/PHP-2005-0923-01-BR.

Interpretive Summary: Weedy blackberry was found in Oregon to be sick or killed from a disease that looks like rust on the plant. The discovery was made in April 2005. The disease is caused by a fungus called Phragmidium violaceum. Identification of the fungus was confirmed by scientists in the USDA-ARS and the USDA-APHIS. More recently, other blackberry plants that are not weeds, but grown on farms, have become sick with the rust disease, too. Although this fungus lives in Europe, South Africa, and Iran, it was also used in Australia, Chile, and New Zealand to control blackberry, which is a weed in those countries. Scientists in Oregon now are trying to see how many of both the weedy and commercial blackberry plants are sick and how the disease might be stopped or controlled.

Technical Abstract: A rust disease was discovered in April 2005 to be causing damage to Himalaya blackberry plants in Oregon. It has been identified as Phragmidium violaceum, based on fungal morphology and molecular characterization. Identification was confirmed by mycologists with USDA-ARS and USDA-APHIS. Specimens have been deposited with the USDA, Systematic Botany and Mycology Lab. Since its discovery, P. violaceum was confirmed infecting Evergreen blackberry, an important commercial cultivar in Oregon. This fungus attacks species of Rubus in Europe, South Africa, and Iran, and it has been introduced for biological control of blackberry in Australia, Chile, and New Zealand. This is the first report of P. violaceum in North America. Because it infects a commercially important blackberry cultivar in Oregon, research has been initiated to determine the extent of the infestation and on disease management.