Over the summer, the Philadelphia region had some atypical weather which has caused a more than normal amount of turfgrass death on golf courses. The region had above average rainfall in August and September. During the month of August, the 30-year average for rain is about four inches, but this August it rained 20 inches. This trend continued in September with 10 inches of rain while the historic average is also about four inches. One local superintendent had nine floods onto his course in August and September.
During this period, soils were saturated longer than normal and there were periods of high humidity with nighttime temperatures greater than 70 degrees Fahrenheit. These conditions are a plant pathologist’s dream but a superintendent’s nightmare. Warm weather diseases such as brown patch, dollar spot, Pythium blight and gray leaf spot were more aggressive and persisted longer than normal, which was a main cause of turf death. Even the best fungicide programs could not overcome the combination of abiotic stress (i.e., persistent hot and wet weather, and low light conditions from cloud cover) and high disease pressure.
These weather conditions also contributed to delays with mowing and other agronomic tasks, and then having to get equipment out before turf areas properly dried-down often resulted in scalping and mechanical turf damage. Because of the prolonged saturated soil conditions, many superintendents said, “…the turf (rootzone) never got a chance to drain.” And using a wetting agent, under these extreme conditions, would not necessarily help, because, as also noted by superintendents, “…where’s the water going to go?” As the late Dr. Burt Musser is credited with saying, the three most important aspects of turf management are “…drainage, drainage, and drainage.”
These conditions persisted until the third week of September. Normally, between mid-August and mid-September, superintendents are busy aerating, topdressing, seeding, and sleeping well at night because night time temperatures drop below 70 and grass thrives. Instead, superintendents were making additional fungicide applications, cleaning up flood damage, fixing bunker washouts, and waiting to mow soggy turf areas. Finally, by the third week of September, some were able to start seeding and sodding damaged areas but were running out of daylight as days are getting shorter and the sun angle is getting lower.
In addition, the higher than normal rainfall and warm conditions resulted in quicker than normal breakdown of pre-emergence herbicides used to prevent crabgrass. Thus, there was plenty of crabgrass breakthrough and, in many areas, goosegrass became a problem. Another weed that thrived this summer was yellow nutsedge. Finding a dry time to apply post-emergence herbicides added to the difficulty in controlling those weeds, and, in most cases, a follow-up application was needed.
This summer was also difficult for superintendents to provide normal green speeds, firmness and trueness. Lift, clean, and place were the norm rather than the exception on fairways. Even courses with the larger or more generous budgets struggled with all of the above.
Fortunately, most golf course superintendents rise to the challenges that Mother Nature brings their way. With some extra seeding and sodding and some warm fall temperatures, there is a good chance the turf should be fully recovered by mid-spring.
Doug Linde, PhD
Professor of Turf Management
Delaware Valley University
Mike Fidanza, PhD
Professor of Plant and Soil Sciences
Penn State University