|Hollingsworth, C - UNIVERSITY OF MINNESOTA|
Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 23, 2004
Publication Date: June 1, 2005
Citation: Samac, D.A., Hollingsworth, C.R. 2005. Detection of brown root rot of alfalfa in Minnesota and Wisconsin [abstract]. Phytopathology. 95:S165. Technical Abstract: Brown root rot of alfalfa, caused by Phoma sclerotioides, is associated with stand decline and reduced yield of forage legumes in western Canada and the western U.S. To determine the distribution of the disease in the Upper Midwest, a survey was conducted in the fall of 2003. Alfalfa plants were submitted from Iowa, Illinois, Minnesota, Wisconsin, and Ontario from 104 locations. Total DNA from roots was used in PCR reactions with P. sclerotioides-specific primers. In Wisconsin the pathogen was found in Shawano, Columbia, and Oconto Counties. In Minnesota plants from seven counties tested positive for the pathogen including Marshall, Otter Tail, Pennington, Red Lake, Sherburne, Wabasha, and Washington. No positive plants were found in samples submitted from Illinois, Iowa, or Ontario. Samples submitted in the spring of 2004 from fields with winter injury in Pierce Co. and St. Croix Co., WI, and Winona Co., MN, tested positive for the pathogen. This study suggests that the disease is found throughout Minnesota and may be associated with winter kill.