Nitrogen Levels and Use of a Fungicide Clearly Impact Brown Patch on Tall Fescue

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. 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.