The Evolution of Turf Diseases: New pathogens appear from thin air

Bentgrass dead spot represented an entirely new disease caused by a previously undescribed pathogen. Photo courtesy John Kaminski

By John Kaminski, PhD

Although grey leaf spot was a minor disease in the southern United States, it was known. What about the development and presence of entirely new problems no one has ever heard about? It certainly happens with evolution and is no different in turf.

A good example of a new pest problem emerging in turf occurred on creeping bentgrass putting greens in the late 1990s. This author remembers starting his graduate program at the University of Maryland and seeing the first case of bentgrass dead spot on the second day. When his mentor and advisor Dr. Peter Dernoeden first looked at the sample under the microscope, he was quite surprised—he had never seen anything like it in the past, and was excited to figure out exactly what he was looking at.

After a few months of isolations and a few years of data collection and molecular investigations, it was determined that not only was this pathogen new to turf, but it also represented an entirely new species within the genus Ophiosphaerella. How can a new species suddenly show up on 10 different golf courses from six different states in a single year? Although this author never definitively determined how the pathogen made its way to so many courses at the same time, the fungus was later found on a bamboo-like plant used for packing material in shipments from Asia. This could simply be a case of putting a previously unreported fungus in close proximity to a susceptible host and letting nature do the rest.

However, this was not the only isolated incidence that occurred in the past decade or so. Rapid blight (caused by Labyrinthula terrestris) was another previously unreported pathogen in turf, but quickly made its way onto golf courses in the Western United States where high salinity water was being used.

Read the full article: The Evolution of Turf Diseases

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