Sudden Oak Death Findings in the Midwest
Phytophthora ramorum, the cause of so-called “sudden oak death,” was detected on plant material being sold in garden centers in Indiana and Kansas this spring. The pathogen is not expected to be established in these areas but entered the states via the plant trade.
One source, Kansas State Extension, reported that infected rhododendrons were found in ten Midwest states, all traced back to a common supplier. Nursery plants will remain a major concern in the Midwest. Walmart and Home Depot are listed as two distributors of the rhododendrons, and consumers who purchased suspect material are asked to destroy it.
In 2018, USDA APHIS announced codification of regulations that shift regulatory action based on geographic areas to now based on positive P. ramorum finds outside the quarantine areas of 15 California counties and 1 Oregon county.
Sudden oak death, caused by P. ramorum, was first reported in the U.S. in 1995 and has killed many oaks and tanoaks in mostly coastal areas on the West Coast. Over 100 plant hosts have been identified, including viburnum, camellia, azalea, and European ash. APHIS maintains a list of regulated hosts and plants associated with P. ramorum.