GOLF: On putting greens, do you ever add a little extra N and try to regulate the extra growth with a PGR application?

Yes-when lean
Yes-to mitigate a disease

Update (07/12/2016)

A Fluid Situation

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Mizzou Field Day: Tuesday, July 19th -
Register Now to Learn & Grow

2016 Mizzou Turf & Ornamental Field Day - Next Tuesday, July 19
A. What did we do along the dots and lines to cause this yellowing?
B. The target was curative disease control, but our treatment resulted in something else.
C. Come hear Dr. T. give you the lowdown on the most beautiful flowers you ever did see.
D. See the new building, and learn how MU students are helping to design our new landscape.

We are all set to see you next week! The 2016 Mizzou Turfgrass & Ornamental Field Day is next Tuesday, July 19th at our research facility at South Farms.  As you can see above, we have tons of great information to share regarding turfgrass and ornamental care.  The event is also approved for 0.25 GCSAA CEUs and 3 CEUs to MLNA STAR members.  So get credit for attending, having fun learning, and eating a great lunch. 

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


July extremely different from June

  1. Consistent clouds & rainfall have kept temperatures down, for now. - Source: Pat Guinan
  2. Rains returned in July to break the region out of drought symptoms. - Source: NOAA

 June ended up as the 9th warmest month on record, in line with temperatures experienced in 2010 (no. 8). Rainfall was variable across the state in June, and averaged just 2.5 inches. This was just over 2 inches below average, and the driest since 2012. June contributed to our 6th driest January - June on record (9.43 inches below normal) in Columbia.

As the month flipped to July, so did the weather. On July 2-3, a strong system crept through, delivering constant rains totaling 2.5 to 7 inches in some areas. Another storm system came through on July 6 and t to dump another 1 to 1.5 inches on the region. Along with the rain and clouds, temperatures dipped in early July. In the short term, the current wet weather pattern is forecasted to continue throughout this week. Next week, however, the June pattern looks to return with above average temperatures and dry conditions. Putting greens may quickly show the ill effects of the consistently saturated soils and associated Pythium infection when this stressful weather returns. Cool-season lawns may once again go into drought dormancy, perhaps even into a quick flash drought situation.       

Quick Hits

Basal Rot Anthracnose

  1. Mixed ‘Penncross’/Poa sample symptomatic of anthracnose.
  2. Black darkened plant crown or base is indicative of this disease.

  • Anthracnose on a mixed bentgrass/Poa putting green was submitted early last week.  The combination of heavy rainfall and associated dip in temperatures often preclude these outbreaks, which we also commonly observe again in the fall.  Although some bentgrass cultivars are susceptible (i.e. Penncross, Pennlinks, SR1020, etc.), in this case much of the damage was occurring on the Poa.  

    Researchers at Rutgers University have written the book (or more literally the white paper, which can be found here – BMPs for Anthracnose Control) on control practices for anthracnose on annual bluegrass, which apply well to susceptible bentgrass cultivars.  Suggested fungicide applications for curative control often center on mixing a contact (i.e. chlorothalonil or fludioxonil), systemic (i.e. QoI, DMI, or combination) and a shot of nitrogen to facilitate recovery.  New fungicides such as Briskway (QoI and DMI combo), Lexicon (QoI and SDHI combo), and Velista (SDHI = penthiopyrad) have reportedly worked well for anthracnose control in trials.  These new tools are important since field resistant populations of the anthracnose pathogen have been detected to the QoI and benzimidazole fungicide classes.

Pythium A Plenty

  1. Black, necrotic shortened roots typical of root rot in this sample from SW MO.
  2. Bisporus oospores in this root sample of a newly established green indicate Pythium root dysfunction.

  • As expected with the recent deluge of rainfall, Pythium root rot has been prevalent on putting greens samples submitted to the lab.  We also, however, received a sample from a newly established green in St. Louis that appears to have Pythium root dysfunction caused by Pythium volutum.  These oospores are characteristically bisporus, as shown in the photo above.  Pythium root dysfunction is more likely seen in younger putting greens.  It’s increasingly apparent that both Pythium root dysfunction and Pythium root rot deserve targeted preventive applications throughout the season, particularly on greens with a diagnosed history.  Due to the number of species and propensity for fungicide resistance, Pythium targeting fungicides should be rotated, perhaps on as tight as a 14-day interval during the summer stress periods.  Also, remember these fungicides must be watered in with 1/8” of post-application irrigation to be delivered to the target root zone.  This includes traditionally foliar applied products like Signature Xtra, which Dr. Jim Kerns from North Carolina State University posted recently has a suppressive effect after being watered in.     

Change your Timers!!!
This photo was taken on July 8th. Evidently 6+ inches of rainfall in the previous 5 day span was still not enough on this property.

  • Irrigation on Tall Fescue:  The recent rainfall pattern, associated drought response and subsequent recovery of tall fescue lawns have an obvious lesson.   In June, as we were in the midst of a drought, homeowners and turf managers alike were watering like mad.  Those without in-ground irrigation systems were spending countless hours dragging hoses trying to keep up, oftentimes simply inviting brown patch in to pillage.   Now that the drought has subsided, look around. Neighbors that didn’t water and had brown lawns, now have lawns that look exactly the same as irrigated ones.  This same scenario occurred in the 2012 drought which was considerably more severe. Some tall fescue lawns didn’t receive a lick of water in 7 weeks and still came back to former glory.  Tall fescue has a fantastic drought adaptation mechanism that allows it to go dormant and come back fighting when the spigot turns back on.  As noted in the previous update, why do we fight this brown so vehemently?  As a final note, if you have been fighting the brown, please adjust in-ground irrigation systems to not water when the rains do return.  The above picture shows irrigation last week after 6.5 inches of rain had fallen the previous weekend.  To put it mildly, this really “grinds my gears” as the waste of water resources is painfully obvious to even the slightly mindful passer-by.   


    Have a great week, and hope to see you at field day next Tuesday,


    Lee Miller
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    Extension Turfgrass Pathologist
    University of Missouri