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July 2018; Ctrl-C, Ctrl-V August 2, 2019 By Paul Jacobs, agronomist, Northeast Region

Anthracnose and algae on a bentgrass and Poa annua putting green.

The recent weather – hot, humid and wet – has felt a lot like the summer of 2018. Turf response hasn’t been much different either. Courses that invested in drainage, fans or tree removal in response to a wet 2018 are holding up well this year, despite challenging conditions. However, if changes were not made, this year is providing another great opportunity to identify areas of weakness so that a plan can be put together for future improvements. When evaluating drainage on the golf course, it is always a good idea to “plan when it’s wet, install when it’s dry.”

Some common topics discussed during recent Course Consulting Service visits in the Northeast and practices to help deal with them are outlined below:

Algae – Blue-green algae is common when turf surfaces remain wet for prolonged periods of time. While algae can be an indicator of poor drainage, excess organic matter or overwatering, the recent weather has provided more than enough moisture to encourage algae development. Growing healthy turf is the best defense against algae. Improving air movement, sunlight and drainage are critical to prevent algae. Once algae develops it can form a layer on the surface that will inhibit turf recovery. Venting, light verticutting during favorable weather, and frequent sand topdressing will break through the algal layer, helping the surface to dry and improving recovery. When used in combination with these cultural practices, chlorothalonil and mancozeb are also effective to help manage algae.

Anthracnose – Although no major outbreaks have been observed, small isolated incidents of anthracnose have been common in the past couple of weeks. Slightly raising the height of cut, making regular sand topdressing applications and providing sufficient nitrogen to produce moderate growth will help reduce anthracnose severity. Although the DMI fungicides can be effective to control anthracnose, overuse can result in stressed turf and an open canopy – both of which will promote algae. Use other fungicide chemistries during periods of excessive heat.

Crabgrass and Goosegrass – Most facilities were able to make the necessary preemergence applications this spring, but in some cases high rough areas or primary rough may not have been treated due to extremely wet conditions. Breakthrough has been observed in areas that were treated this spring, and areas that were not treated are easily noticeable. Excessive rain likely plays a role in the breakthrough we are seeing. For better preemergence control in future years, consider splitting the spring preemergence application into two separate applications. To improve preemergence goosegrass control, Ronstar can be applied. If applying Ronstar to cool-season turf, use the granular formulation and apply when the foliage is dry. There are several options for postemergence control of these weeds, but herbicide selection depends on the type of turf being managed. Contact your regional USGA agronomist for information on postemergence control options that meet your specific needs.

2019 hasn’t been an easy year so far, but look at the glass as half full and use this summer as an opportunity to educate stakeholders as to why improvements such as drainage, selective tree removal and perhaps installing fans is necessary to improve turf health and reliability.


Northeast Region Agronomists:

David A. Oatis, regional director –

Adam Moeller, director, Green Section Education –

Elliott Dowling, agronomist –

Paul Jacobs, agronomist –

Information on the USGA’s Course Consulting Service 

Contact the Green Section Staff

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