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Update (8/30/2012)

Isaac in MO Hooray! PRR would not be OK

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Weather was relatively mild in August compared to the rest of summer 2012.  Rain has been scarce, particularly in mid MO.

August temperatures have been a blessing with a slight above average monthly temperature (+2.5°F) compared to the previous July, which ranked as 5th highest all-time.  Cooler temperatures were nice and aided in turf recovery from this brutal summer.  Precipitation did occur for many on 8/26 and 8/27, with about 1” in St. Louis, 0.5” in Kansas City, and 0.3” or so in Springfield.  Don’t brag to those of us in mid Missouri or in the Bootheel, as we got none, zero, and zippo from the previous system.  Columbia, MO may be the poster child for this current drought, and the lack of precipitation numbers are staggering.  We will have the driest May 1- August 31 period in the 123 history of recorded weather, unless we get 0.64” of rain tomorrow.  Drier than the dust bowl era, drier than 1911.  The current deficit is running at about 13.5” in the hole.  Believe it or not, this is not the “driest span” in history as pointed out by our state climatologist Pat Guinan.  From January 1952 – December 1956, the total deficit was 48.09”, and an extraordinary 46 out of 61 months had below normal precipitation.  So it could be worse…  but not much.  Trees are defoliating all throughout mid MO, and many landscape plantings are beyond recuperation. 

For this reason, now tropical depression Isaac may be just what the doctor ordered for Missouri.  This statement is made with all due respect to the destruction that has occurred in Louisiana and Mississippi, but this tropical system is exactly what this region needs.  The first tiny wave of precipitation is hitting southern MO now, and hopefully minus the tornadoes or other severe weather, we will get a good multi-day soaker.  If it’s out by 6 pm on Saturday for the first Mizzou football game that would be a bonus, but I could handle getting rained on a little to receive the great benefit.   

Quick Hits

Tropical depression Isaac could be the drought buster this region needs.


I mentioned renovation in the previous update, but reseeding may need to wait until after TD-Isaac passes.  I realize it’s kind of late to mention now, but I didn’t want to jinx it!  The rain (hopefully we get it) will do a few things – potentially positive and negative.

#1 The system should green up truly dormant turf, and allow for identification of truly dead areas.  Finding out what areas are not going to recuperate may save in seed costs. 

#2 The first wave of precipitation will probably not hit receptive soils.  Water will run off or into cracked clays and potentially drag small turf seed with it.  Seed down gutters doesn’t do much good.  If seed has been applied recently, it may help to put mulch or pine straw down tomorrow to keep it in place. 

#3 Previously unworkable soil may become workable again early next week.  Unfortunately, this is not the time to aerify zoysia lawns/fairways as it may spark unwanted infection by the large patch pathogen.  However, if reseeding is your aim, lightly scarring the soil surface to ensure good seed-soil contact will be beneficial and much easier after the system passes. 

Diseases to Watch For

Pythium and Rhizoctonia damping off diseases of seedlings should be watched out for.

No diseases have come into the diagnostic lab in the last two weeks.  However, it is necessary to put out an alert for Pythium root rot and damping off diseases since leaf wetness and saturated soils may finally occur throughout Missouri.  For golf courses, root health on bentgrass putting greens are in the first stages of recovery, and maybe vulnerable to attack.   On golf greens with a history of Pythium root rot (PRR), a watered-in preventive fungicide application of Banol, Segway, or Subdue may be warranted.  For those that have seeded a few weeks ago and have young seedlings established, it would be wise to closely monitor them after the storm passes.  Damping off diseases caused by Rhizoctonia and Pythium spp. can be prevalent and devastating in saturated conditions, and the kick from a starter fertilizer can be the fuel to that fire.

As an aside, the national plant pathology society I belong to, (the American Phytopathological Society) just released a video promoting our profession.  Not a lot of exposure for turf, but it is a window into the types of research conducted by plant pathologists.  If you have some time while its raining, you can view it at the link here.     

Short updates normally mean good news.  Hopefully we all can enjoy the rain!

Go Tigers!   

Lee Miller
Follow on Twitter!  @muturfpath
Extension Turfgrass Pathologist
University of Missouri