Quick guide: Manage anthracnose and rapid blight on Poa annua greens

By Lisa Beirn, Ph.D. and Ron Townsend, M.S., technical services managers for Syngenta

Rapid blight | Anthracnose | Treating rapid blight and anthracnose

Rapid blight

  •  Issue: Rapid blight is a turfgrass disease that can affect Poa annua, Poa trivialis and perennial ryegrass species
  • Symptoms:
    •  Patches of chlorotic turf that can be several feet in diameter
    • On low cut turf and putting greens, may have dark brown boarders
  • Challenges:
    • It most closely resembles a pathogen of marine grasses
    • Disease severity is correlated with saline irrigation water and soil salinity 
  • Management strategies:
    • Carefully monitor and manage salinity
    • Use tolerant species in winter overseeding
  • Fungicide applications challenges:
    • A limited number of fungicides effectively suppress rapid blight’s severity
    • Continuous applications of a single mode of action fungicide can cause a shift in pathogen sensitivity
    • Managers of Poa annua greens need to implement a preventive fungicide program to not only control rapid blight, but other key diseases like anthracnose, brown ring patch and summer patch
  • Issue: Anthracnose is one of the most destructive diseases of Poa annua putting greens across the country
  • Symptoms:
    • Foliar blight
    • Basal rot
  • Challenges:
    • Severe on stressed turf
  • Timing: Can be found on greens from the spring through the fall
  • Management strategies:
    • Preventive fungicide program combined with cultural practices

Treating rapid blight and anthracnose

Ascernity® fungicide is a systemic fungicide that contains SOLATENOL® technology, a SDHI (FRAC code 7) and difenoconazole, a DMI (FRAC code 3), for broad-spectrum disease control including anthracnose, brown ring patch, and rapid blight on Poa annua putting greens (2ee label).  A sound agronomic program for disease control will include rotations and tank-mixes of chemistries with different modes of action. The Syngenta disease management program for Poa annua greens in California includes Ascernity, Velista®, Heritage® Action™ and Heritage TL fungicides in combinations or rotations with Secure® Action™ or Daconil® Action™ multi-site contact fungicides. This strategy controls all the key Poa annua diseases for a robust greens fungicide program. Daconil Action + Heritage Action and Ascernity + Posterity® XT fungicide are sold in a convenient Multipak for added value.

In a University of California Riverside trial Ascernity, Velista and Secure Action fungicides were applied to a Poa annua putting green with a history of rapid blight and anthracnose incidence. Applications were made on a 14-day interval from June-September and ratings for presence of disease and turf quality were recorded. Ascernity, Secure Action and a tank mixture of Velista and Secure Action showed outstanding rapid blight and anthracnose control at the end of the trial. Ascernity applied alone effectively suppressed these diseases (see image below).

Control of Rapid blight/Anthracnose on Poa annua with New fungicides UCR 2015.
% disease rated 14 days after last application

University of California, 2015. Fungicides applied on 14-day intervals starting in early summer. 

A greenhouse trial at Clemson University in 2015 shows the benefits of tank-mixing Secure Action with Velista or Heritage fungicide (or with Heritage Action) for control of rapid blight on perennial ryegrass.

To learn how to prevent rapid blight and other key turf diseases as part of an agronomic program, visit www.GreenCastOnline.com/Programs

All photos are either the property of Syngenta or are used with permission.

Performance assessments are based upon results or analysis of public information, field observations and/or internal Syngenta evaluations. Trials reflect treatment rates and mixing partners commonly recommended in the marketplace.

© 2024 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties and/or may have state-specific use requirements. Please check with your local extension service to ensure registration and proper use. Syngenta supports a FIFRA Section 2(ee) recommendation for Ascernity to suppress rapid blight on Poa annua greens. Please see the Section 2(ee) recommendation to confirm that the recommendation is applicable in your state. The section 2(ee) recommendation for Ascernity should be in the possession of the user at the time of application. Action™, Ascernity®, Daconil®, GreenCast®, Heritage®, Posterity®, SOLATENOL®, Velista®, the Alliance Frame, the Purpose Icon and the Syngenta logo are trademarks of a Syngenta Group Company. Secure® is a trademark of Ishihara Sangyo Kaisha, LTD. All other trademarks are the property of their respective third-party owners.

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