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What You Need to Know about the Sudden Oak Death Threat in Indiana
Photo Credit: United States Department of Agriculture, Joseph O'Brien, Forest Service
Last week the Indiana Department of Natural Resources announced a found string of disease-causing pathogens in common shrubs, most notably rhododendrons, which can quickly kill any oak tree within 6 feet of the plant.
The pathogen, phytophthora ramorum, has been found broadly in the West Coast since the 90s, lingering and killing trees in forests and damp cool climates such as Oregon and Washington State. Now this fatal disease has made it’s way to the Hoosier state.
As it says in the name, SOD (Sudden Oak Death) is just that- a quick sudden end to any oak tree. Not only is the disease dangerously fast acting, another problem is there is no cure.
The DNR say if an oak is infected it will cause cankers on the tree. The oak will quickly appear weak and dark fluid will start to come out of the bark.
Note: This particular disease only affects the oak tree, primarily the red oak, and doesn’t hurt the hosting plants.
“It actually doesn’t kill the nursery stock it travels in, which is what makes it such a dangerous pathogen. It kind of hides within the nursery stock," says a DNR representive.
How to identify plants hosting SOD
Megan Abraham, from the IDNR Division of Entomology and Plant Pathology, describes what to look for in a possible infected rhododendron.
“We are looking for browning in the leaves. It will look like it’s almost overwatered or scorched a little bit. It’s around the margins of the leaves.”
Other shrubs to monitor include rhodies and azaleas which are apart of the rhododendron family. In addition, a few native viburnums such as Allegheny and the American Cranberry viburnum can serve as host plants.
Abraham points out that it may take some time for the symptoms to show in your plants.
“The problem is many of these plants were sprayed with fungicide before they have been purchased, which means you won’t see any symptoms for about 30 days.”
To get a full diagnosis you can contact the DNR at 1-866-NO-EXOTIC (663-9684.)
This specific case
Officials have said that any rhododendrons purchased from Wal-Mart or Rural King in the last month should be destroyed.
Infested shrubs were found in over 88 stores in Indiana. Locations include Noblesville, Columbus, South Bend, Sullivan, and Lafayette.
As of May 29th, 1,500 infested plants have been destroyed and another 1,500 have been pulled from stores.
Check out the full interview with the DNR below