Flood Injury And Pythium Blight

We have a few areas on the course that have suffered from flood injury and pythium blight again this year.  Dr. Settle wrote about this in the August 5 Turf Scouting Report.  Here is what he highlighted:

Plants are in survival mode as July transitions to August. A difficult time on Chicago golf courses as it's our historical period of cool-season turf physiological decline.  We've been trough another difficult summer and weather is to blame.  Sound familiar?  As August starts, the coming weeks are important because further environmental stress will encounter plants with little roots, few stored reserves and abnormal physiology (respiration exceeds photosynthesis and roots are without growth).  A return of cooler night-time temperatures will help us begin to lose soil heat which has been building all summer.  Cooler soil will mean normal root growth will begin anew as photosynthesis efficiency returns.

On Monday this week several superintendents had scouted a few serious issues that followed our latest series of 90 degree F highs.  Pythium blight has been very active this summer because our high temperatures have not limited its developement.  Pythium commonly occurs during or just after a period of 90+ degree highs.  At one course that recently flooded, Pythium blight broke through a newer fungicide six days after application.  Others have experienced about a week of Pythium blight suppression during similar periods.

Our fairways that are most severely damaged from flooding and pythium are 11 fairway and 16 fairway.  Other fairways are showing damage around drainage basins or drainage patterns.  This damage occurred on July 28th after 0.90 inches of rain.  The soil was already very wet, so this rain had nowhere to go and sat on the surface for most of the day.  The low temperature for the day was 72 degrees, and the high was just short of 90 degrees.  This makes a great environment for pythium and physiological decline of the turf from sitting in hot water throughout the day.

This area on 16 fairway was flooded most of the weekend of July 23-24 and into Monday July 25th.  The standing water was off of the fairway by Tuesday the 26th, but the soil remained saturated through the heat a few days after.  This area is in the floodway of the course and is designed to take the overflow from the pond on 17.

This area on 9 is also in the floodway and was flooded on the same weekend as well.  This area did not hold water as long as the area on 16 do the damage is less severe.  This area will still require over seeding.

This picture is a great illustration of the importance of drainage to soils, and the superiority of bentgrass to annual bluegrass to varying conditions.  Click on the picture to see it better.  The drainage lines that were put in this area last fall are obvious to see.  This area was flooded the same weekend, but this drain was able to remove more water from the soil than the other areas that did not have any internal drainage.  The thin areas around the drain are comprised of mostly annual bluegrass, which is thinning from the prolonged high soil moisture and temperatures.  We are planning to add more drain lines this fall to areas in the fairways.

This is a drainage pattern in 8 fairway that showed pythium on July 28th after the 0.90 inches of rain and warm temperatures.

11 fairway has suffered the most damage from this bout of weather.  It is notoriously our most poorly drain fairway.  Pythium was the most widely spread on this fairway also.

We will begin to over seed these areas soon.  Like last year, it will take most of the fall for these areas to heal back in.  This weather today has made a turn for the better, and the 10 day forecast is very appealing at this point.