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Are bermudagrass decline and take-all root rot the same thing?

By Lane Tredway, technical services manager for Syngenta

Bermudagrass decline and take-all root rot are often considered to be synonymous, but they are actually very different issues. Bermudagrass decline is a complex of stresses, whereas take-all root rot is a root disease caused by a specific pathogen. Simply put, take-all root rot is part of the bermudagrass decline complex.

Bermudagrass decline isn't caused by a single pathogen, but by a combination of physiological stresses and a variety of pathogens. Anyone who’s grown creeping bentgrass in the transition zone is familiar with summer bentgrass decline – the combined effect of high temperature and humidity with stress-related pathogens like anthracnose, Pythium and algae. Bermudagrass decline is a similar phenomenon. Cool temperatures, cloudy weather, extremely close mowing and other stresses create a plant that is highly susceptible to a variety of pathogens, including take-all root rot, leaf spot, Pythium species and nematodes, which speed up the decline of the stressed turf or kill it outright.

Even though bermudagrass decline is not a disease, routine fungicide applications are an important part of the solution. Many of the contributing factors (weather conditions, event schedules, golfer expectations and water quality, to name a few) are out of the superintendents’ control, but a comprehensive agronomic program to protect the stressed turf can help to maintain acceptable turf quality. Broad-spectrum fungicides or tank-mixtures, such Secure® Action™ or Daconil® Action + Appear® II fungicides, are key components of an agronomic program and have been shown to prevent bermudagrass decline in university research trials.

Bermudagrass decline control on TifEagle bermudagrass
 Treatment comparison

Treatments applied October 23, November 1, November 13, November 29 and December 17, 2018; and February 14 and March 4, 2019. Photos taken March 12, 2019. Performance assessments are based upon results or analysis of public information, field observations and/or internal Syngenta evaluations. Trials reflect treatment rates commonly recommended in the marketplace. Source: Prestwick Country Club, 2018-2019.

The fungus Gaeumannomyces graminis var. graminis is a common contributor to bermudagrass decline, but it is also a bonafide pathogen causing take-all root rot even in the absence of stress. Gaeumannomyces graminis var. graminis is a hot-weather fungus, but most infection occurs from late summer to spring when it has a competitive advantage over slowly-growing bermudagrass roots. Combination products that contain azoxystrobin, such as Briskway® and Headway® fungicides, are key applications during this time to protect bermudagrass roots from infection by this fungus.

Syngenta agronomic programs for bermudagrass putting greens are designed to prevent both bermudagrass decline and take-all root rot. Many of the applications from late summer through spring are targeted to prevent take-all root rot and the variety of pathogens that contribute to bermudagrass decline. These programs have been shown to improve the winter quality and spring green-up of bermudagrass putting greens.

For more information about agronomic programs from Syngenta, visit GreenCastOnline.com/Programs. You can also download the GreenCast® Turf App for both Apple® and Android® smartphones and tablets to help streamline the tank-mixing calculation and record-keeping process.

Photos are either the property of Syngenta or are used with permission.

©2019 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. Action™, Appear®, Briskway®, Daconil®, GreenCast®, Headway® and the Syngenta logo are trademarks of a Syngenta Group Company. Secure® is a registered trademark of Ishihara Sangyo Kaisha, LTD. Apple® is a trademark of Apple Inc. Android® is a trademark of Google Inc.