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K-State Turf and Landscape Blog

Tag: disease research

Nitrogen Rate and Fungicide Had Big Impact on Brown Patch in Tall Fescue this Summer

If you were at field day on August 3rd, you likely saw the experimental area that was highlighted by Dr. Megan Kennelly.  A turf-type tall fescue blend has been treated the past two years as either: High N level; or Low N level.  High level involved 4.5 lbs of N/1,000 ft2/yr  (Months applied listed in lbs N/1,000 ft2 – 1 in April; 1 in May; 1.5 in Sept.; 1 in Nov) and low N level was 1.5 lbs of N/1,000 ft2/yr (single application in September).  In addition, half of the plots receiving these treatments either received two fungicide applications from azoxystrobin (Heritage) each growing season or none.  You’ll see a photo below of how N impacted brown patch on tall fescue.  More details will come out in the 2024 K-State Turf Research Report.  Bottom line summaries:

  • High N levels provided high quality turf, but fungicide application was required to maintain it when brown patch infection began.  Turf receiving high N without fungicide declined quickly in quality starting in July.
  • Brown patch levels were comparable in July in turf receiving high N from standard urea, humic coated urea, or combinations of 50% slow release + 50% quick release N.
  • Low level N generally provided turf quality that was at or just below an acceptable level (but not high quality) and had little brown patch even when fungicides were not applied.

    Impact of N level on brown patch in tall fescue with no fungicide application.