SPORTS TURF: Have you fraze mowed your bermudagrass fields?

Yes-more than once
Yes- once heavily
Yes- once lightly
Don't manage bermuda

Update (06/27/2016)

The Turf is on Fire

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June Heat Primed to Enter the Record Books
A.  90 degree temps have been the norm since June 8. - Source: Pat Guinan  
B.  Average departure from mean temperatures for June 1 - 20. - Source: Midwest Regional Climate Center

This June has been a doozy, with now 18 straight days with above 90 degree high temperatures in Columbia.  Currently, most of Missouri is 4 – 6 degrees above normal now, with the record books being in sight for the month.  Even with the cool down expected coming Tuesday into early July (see below), average temperatures are expected to near or eclipse those of 1953, possibly making it the third or fourth warmest June on record.  

Along with the heat, a persistent drought pattern has remained over much of Missouri.  Welcome rains over the middle portion of the state dropped 0.5 – 1 inch of precipitation early last week with locally higher amounts in the northwest and southwest Missouri.  A nice douse of rain yesterday also provided mid Missouri with 0.25 – 0.5” of additional precipitation.  Over the last 30 days, however, the I-70 corridor from St. Louis - KC and most of central Missouri have suffered intense drought with 2 – 4” precipitation deficits over the time frame.  As stated in the previous update, this is accompanied by high evapotranspiration rates of over 0.25 inches on most days for a total of over 5 inches of ET lost for the month.  The forecast doesn’t call for much relief, and as often is the case a drought pattern is expected to perpetuate a drought pattern.  The drought monitor still has much of central and northeast Missouri (Columbia into St. Louis) listed as abnormally dry.

6-10 Day Outlook: Desired Cool Down, Still Dry
A.  A forecasted, and would be fortunate cool down expected next week. - Source: NOAA CPS
B.  The drought for Missouri is expected to continue for the state.  - Source: NOAA CPS

Quick Hits

  • Brown Patch/Pythium on Tall Fescue: As indicated in the last update, if a tall fescue lawn is irrigated and in the shade, it is extremely prone to brown patch this time of year.  We have considerably large outbreaks of brown patch at the turf farm now, and with the heat and high temperatures some Pythium may also be on the prowl.  Azoxystrobin (Heritage) can be considered for disease control now since it provides excellent control of brown patch and some preventive control of Pythium. 
  • Chinch bugs on Zoysiagrass: A report came in last week of a severe outbreak of chinch bugs on his zoysiagrass lawn.  The sustained heat has spurred their activity and subsequent damage, which can mirror drought symptoms.  Do not mistake this damage for large patch, which is over and done at this time of year.  Chinch bugs also prefer full sun, and most damage on zoysia will stop at shade lines.  Curative control with a pyrethroid or other contact insecticide is recommended, but take care to apply with reduction of non-target effects in mind.  Scouting for chinch bugs is most effective along sidewalks and driveways since they are small (size of FDR’s nose on the dime) and the adults are dark colored.  You may also cut a chunk of turf from the outside margin of a suspected area and put it in a sealed plastic bag on a hot sidewalk.  If present the chinch bugs will try to get out of the plastic sauna and are easily noticed.

Strange Bedfellows: Pythium Root Rot and Localized Dry Spot
A.  Pythium root rot noted on roots of bentgrass putting green sample from Kansas City. 
B.  The sand was also hydrophobic in the sample resulting in typical LDS symptoms.

  • Double Root Whammy:  A sample was submitted in mid June from the Kansas City area that was a first for me.  The roots were clearly infested with Pythium spp. causing root rot while the same sample was also suffering from hydrophobic soils and localized dry spot as evidenced with a water droplet test.  It’s important to recall recent weather KC history and the stand symptoms (shown above) to understand how this may have occurred.  May was particularly wet in Kansas City and soils were saturated at the infection period when Pythium root rot would be rolling.  Only since June has Kansas City been afflicted with this “flash drought”.  Symptoms were the result of a double whammy of previous Pythium infection when wet to compromise the roots, and the quick pop of localized dry spot, which is brought on by quick wet/dry cycles.  The superintendent applied Koban/Terrazole as an opening jab, followed with a wetting agent and venting, and then closed with a Segway + QoI fungicide combination.         

Fairy Ring Popping on Putting Greens
A.  Puffballs, joined by dollar spot and brown patch on one of our research greens.
B.  On newer greens, fairy ring tends to come in from the outside in.  Type II green rings are transitioning to hydrophobic and necrotic Type I rings in the current dry weather.

  • Fairy ring on putting greens: Fairy ring has been reported at several sites in the region, and is very prevalent now on some of our research greens at the turf farm.  The disease is very prominent on a younger green that was built in 2012, with puffballs being produced on it and several other greens.  Fairy rings will often first invade the sand-based profile from the outside collar in, as shown in the above picture.  At this point, the DMIs will not be effective in controlling the disease, and a multi-pronged approach of relieving the soil hydrophobicity and stopping the fungus will need to be employed.  A tank-mix of flutolanil (ProStar), azoxystrobin (Heritage), pyraclostrobin (Insignia) along with a wetting agent is recommended for control, along with an aggressive solid or core aerification along ring margins to encourage water infiltration.    
  • Avid purchase for use as nematode control on putting greens is coming to a close this week.  As has been reported over the last few weeks, the 24(c) Special Local Needs label will be cancelled on June 30, 2016 so purchases will no longer be permissible.  Superintendents have an additional year until June 30, 2017 to use existing product, including the Multipak that was available in conjunction with Heritage and Heritage Action fungicides.  A new nematicide from Syngenta is expected to replace Avid in 2017, along with nematode products from various other companies, so stay tuned…

Algae and Yellow Spot on Putting Greens
A.  Yellow spot can be caused by toxins released by blue-green algae. 
B.  Crowns and leaf sheaths of affected bentgrass plants are infested with algae.

  • As was observed prevalently in mid June 2014, samples and reports of blue-green algae (cyanobacteria) and resulting yellow spot outbreaks have occurred in the last few days.  Cyanobacteria can compete with other organisms by producing toxins, excreting siderophores to compete for iron, or clogging soil macropores and creating a black layer condition.   They have also been implicated as the cause of a disease known as yellow spot, which involves a distinct chlorosis presumably resulting from the toxin.  Cultural practices to reduce this problem rely on drying down the turf surface and mat layer through careful irrigation.  Additionally, vent tining on a regular basis may greatly aid in the dry down and algae reduction.  Regular applications of chlorothalonil and mancozeb may aid in algae reduction. QoI fungicides (Heritage, Insignia, Compass, etc) may result in higher levels of yellow spot, so a regular application schedule of chlorothalonil may be necessary to maintain adequate algae levels when QoIs are applied.  For a more complete summary and explanation of cyanobacteria effects on putting greens, click here to read a great research article written by Tredway, Stowell, and Gelernter

The Turf, The Turf, The Turf is On Fire

Drought/Heat + Traffic Plague Cool Season Turfgrasses
A.  Traffic or mowing on heat & drought stressed lawns will lead to considerable damage.
B.  High traffic areas on sports fields can also suffer damage if not enough water is available.

Obviously, the rest of the song’s chorus referenced above is extremely inappropriate, but this particular line is very poignant in pointing out the current situation for cool season turfgrasses in Missouri.  Many samples of drought stressed lawns, and even some sports turf have been submitted over the past two weeks.  Some of the pictures, as in the left panel shown above, seem horrific. 

This article was started late last week, and most of Missouri received a good amount of rain (0.3 – 0.5) yesterday for a bit of a recharge.  Overall, though, mid Missouri is somewhere around 8-9” below normal for the year thus far, which harkens back to thoughts of the 2012 drought.  The 2012 drought started earlier and was a much more widespread phenomenon than this year, spanning most of the Midwest and Midsouth regions (see below).  Dew points and humidity were also much lower in 2012 then 2016, which perpetuated higher and sustained amounts of heat and drought stress in plants.  Still if looking at Columbia weather data from June 1-25 alone, temperatures have been higher in 2016 than 2012 (88.1 F average daily high vs. 86.4 F) and less rain has fallen (0.76” vs. 1.21”).  

The most severely impacted areas had traffic or were continually mowed despite being drought & heat stressed, and/or were watered inefficiently. Drought stressed or dormant turfgrasses should not be mowed or excessively trafficked.  Footprinting after walking on the lawn or a crunch sound under your foot is not a good sign.  Most importantly, if it’s not growing there is no need in mowing.  Non-irrigated cool season turfgrasses on our research farm haven’t required mowing in the last three weeks.

The pursuit of the color green in a drought situation such as this can lead to more problems than good.  Tall fescue, and to a much lesser extent Kentucky bluegrass, has a good drought tolerance mechanism that results in the plant going dormant.  This dormancy appears as an even light brown to tan appearance in dormant tall fescue, and in tough to irrigate or non-irrigated areas this is a good thing.  Watering inefficiently (pulling a hose around every once in a while) doesn’t allow the plant to go into dormancy efficiently and keeps it teetering back and forth in a weakened state, making it susceptible to disease, heat, and traffic stress.  In addition, many homeowners water in the evening, which may be convenient, but can spur disease outbreaks such as brown patch and Pythium.  In 2012, dormant tall fescue came back just fine the next fall when the rains returned after 7 straight weeks without a drop of precipitation.    

The 5” of short crop evapotranspiration lost from June 1 - 23 equates to over 135,000 gallons of water per acre, or on a normal lawn of 0.2 acres about 27,154 gallons. For the recommended 70% replacement, a homeowner would have had to apply over 19,000 gallons of water this month alone to keep up with the deficit.  Those pulling hoses around on lawns throughout June have had little chance to effectively put out this much water and keep cool season turfgrasses out of dormancy.  At some point early in a summer drought, those that can’t water well shouldn’t water at all, and should stop killing their lawn with the kindness.      

Comparing 2016 to 2012

A.  In June 2012, the drought was considerably more pervasive and severe in the entire Midwest. - US Drought Monitor
B.  The June 2016 drought is more centralized over Missouri and parts of western IL and southern IA. - US Drought Monitor

Mizzou Field Day: Tuesday, July 19th -
Schedule is Set… Register Now!

Registration is open and the schedule is set for the 2016 Mizzou Turfgrass & Ornamental Field Day, to be held July 19th at our research facility at South Farms.  We have a ton of great education for you to parlay into healthier grass and better landscape with greater knowledge and an enhanced management scheme. See the entire schedule below.

Registration for both attendees and exhibitors can be found at the new site:

For more information, feel free to contact me or Kevin Dern at




Lee Miller
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Extension Turfgrass Pathologist
University of Missouri