Department of Plant Pathology
North Carolina State University
Much of North Carolina experienced a wet spring that has transitioned into a typical summer with afternoon thunderstorms bringing varying amounts of rainfall to different regions of the state. This added moisture has led to an increase in Pythium root rot activity on creeping bentgrass putting greens across much of North Carolina in recent weeks, in fact it has been the number one diagnosed disease on creeping bentgrass by far at the NC State Turf Diagnostics Lab.
The symptoms of Pythium root rot are typically very irregular in shape and tend to have no set pattern about the distribution, however a patch type symptom may be observed on occasion. These affected areas often start out looking orange and/or yellow and turn brown and/or tan rapidly. Although damage is usually worse in poorly drained or low lying portions of a green, it is not limited to those areas and can even be found on humps and ridges.
Fungicides are available for Pythium root rot control, and should be applied prior to forecasted wet periods or shortly there after. Just remember that when applying fungicides for Pythium root rot you will need to water the product in to the depth of your root system, which can vary greatly from course to course.
For more information about Pythium root rot and preventative fungicide programs, please visit the following links:
For information on submitting disease samples : http://ncstateturfdiagnostics.com/TDL/Sample_Submission.html