Protecting Minnesota’s Pine Resource from Heterobasidion Root Disease

While some might know it as a beautiful conifer, the red pine means much more to the state of Minnesota. In fact, the red pine is a valuable natural resource to the state, and is used for poles, lumber and high-grade paper to name a few, and is also the Minnesota state tree.

Plant Pathology Graduate Student Eric OttoBut red pine (and also white pine) faces an emerging disease threat, which is the focus of graduate student Eric Otto’s research. Heterobasidion root disease (HRD) is a caused by a fungal pathogen (Heterobasidion irregulare) that is considered to be one of the most destructive diseases of conifers in the northern parts of the world. Originally found in Wisconsin in 1993, the disease was recently confirmed to have spread to northern Winona County in Minnesota.

Prevention of this disease is key, as it is difficult to identify, treat and control. A major challenge is early detection, as the disease is difficult to visually confirm. While the pathogen creates fruiting bodies, those fruiting bodies can take 3-6+ years to form after the tree has been colonized by the pathogen, and without visible fruiting bodies, HRD symptoms can be easily confused with other pine root diseases such as Armillaria and red pine pocket mortality. Once HRD is in a stand of pine trees, it is difficult and expensive to manage and control since it takes heavy machinery and often involves intensive site disruption.

That’s why Otto, a Ph.D. student (working with Bob Blanchette) who was a recent recipient of the Carl and Johanna Eide scholarship, and collaborators from the Minnesota Department of Natural Resources, are working together to conduct surveys throughout Minnesota to find the disease early on, so forest managers have the opportunity to plan and initiate proper management techniques to slow the spread of the disease.

With the support of the Minnesota Environment and Natural Resources Trust Fund, Otto is also researching the biology of little-known species of native fungi that interact with H. irregulare to test their ability to act as potential biological control agents to use for management of HRD.

“As a whole I believe and hope that these methods will help maintain and protect our valuable pine natural resources in Minnesota and the Midwest,” says Otto.