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Anthracnose basal rot

July 8, 2009

The multitude of summer stresses appears to be in full swing. This morning on my way to mow some of my research plots I spotted a black cutworm, masked chafer, and some brown patch. I have also heard some grumblings about anthracnose. Anthracnose can be one of the most difficult diseases to control, especially after symptoms develop. As with all diseases and insects, the first step in management is proper identification so you know what you are dealing with.

On a mixed stand of annual bluegrass/creeping bentgrass the symptoms of anthracnose often appear in a patch-like arrangement (picture on right). This is because the anthracnose will usually only infect one of the species, although in rare cases it can attack both. Infected poa will display a yellowish/bronze appearance while infected bentgrass appears droughty. The way I prefer to diagnose anthracnose is with a 30X macroscope. You can usually see the fruiting bodies embedded into the leaves and sheathes (picture below). However, be careful not to misdiagnose a recent application of organic fertilizer for the fruiting bodies of anthracnose. (I have made that mistake before).

I was always told the best way to manage anthracnose is through a combination of preventative fungicide applications and cultural practices that reduce stress on the plant. Fungicide applications made after the symptoms have developed are usually not very effective. There have been reports of disease resistance developing from persistent use of the MBC, DMI and QoI fungicides (Methyl Benzimidazole Carbamates, DeMethylation Inhibitors, and Quinone outside inhibitor). Avoid sequential applications of these products and tank mix with a contact fungicide to help prevent fungicide resistance from developing. Anthracnose can overwinter in the crown and roots of infected plants and a “clean up” fungicide application shortly before winter may also help in preventing the severity of the disease the following year. If anthracnose still occurs, recommendations usually include light fertilizer applications and the stoppage of any plant growth regulators.

Marcus Jones

Graduate Research Assistant


Diagnostic Update: One of our more serious fungal diseases arrived last week

June 27, 2011

This post comes to us from Dr. Derek Settle from the Chicago District Golf Association

Late last week, I heard word that a green was thought to be showing symptoms of anthracnose basal stem rot.  On Monday, in the rain, I made the visit.  Indeed the green did have the typical signs.  Poa annua was bright yellow whereas creeping bentgrass was fine.  Areas of the green that would tend to show wilt stress were most affected.  With a hand microscope that the Superintendent sues for field diagnosis, we both were able to see hair-like state and black discolored stems.  The stems were easily detached when pulled because they had rotted.


The main cause was determined to be two-fold. 1) The weather.  Coincidentally, I had noted that low relative humidity values were striking on Monday and Tuesday (this was already unlike season 2010 which always seemed blanketed in high humidity).  The timing of the outbreak on Wednesday suggested the primary stressor was midday wilt.  2) Some DMI fungicides used for fairy ring prevention have little efficacy against anthracnose basal stem rot.  Our course of action was to reduce plant stress on affected greens.


Reduce wilt stress: monitor greens closely for midday wilt.

Reduce fertility stress: increase nitrogen input as is feasible.

Reduce mowing stress: raise height of cut as is feasible.

Select best fungicide: use published fungicide trial information from plant pathology researchers across the United States.


For up-to-date fungicide recommendations I suggest the University of Kentucky 2011 Chemical Control of Turfgrass Disease guide


Derek Settle, PhD
Director of Turfgrass Program
Chicago District Golf Association
11855 Archer Ave
Lemont, IL 60439