North Central Research Station

Red pine shoots killed by shoot blights.
Photo by M. Ostry

The issue

Clearcutting followed by intense fires had degraded the majority of midwestern pine forests by 1900. Restoration of these degraded lands resulted in large areas of even-aged single pine species. Many of the diseases that have had the largest impacts on these pines were the result of nursery practices that inadvertently spread damaging disease organisms, some native and some exotic, on the planting stock. Over the years researchers developed guidelines to deal with these diseases.  However, with the current desire to develop pine stands of mixed species and ages, some of the previous diseases and some new ones are now having serious impacts on management goals.  Shoot blights of red pine (Pinus resinosa) are such diseases. The fungus Sphaeropsis sapinea causes shoot blight on large trees, shoot blight and cankers on sapling and pole-size trees, and shoot blight and collar rot on seedlings. Another fungus, Sirococcus conigenus, causes a shoot blight that damages or kills red pine seedlings, saplings, and young shoots on older trees.

What are we doing about it?

We are working with other scientists and forest managers to study the interactions of these organisms for developing strategies to avoid or minimize their damaging effects.

We are working with a large group of researchers on a study to determine the effects of retaining mixed species, mixed ages, and variation in canopy gap size in reducing shoot blight inoculum.

We are researching the potential role of fire in reducing shoot blight inoculum with collaborators from Michigan Technological University and the Forest Service Northeastern Area State and Private Forestry.