G1918

Anthracnose of Turfgrass

Anthracnose is a fungal turf disease most often found on bluegrass or bentgrass. This NebGuide describes the disease and how to best manage it.

• Introduction
• Cause, Hosts, and Occurrence
• Key Symptoms
• Cultural/Maintenance Practices
• Fungicide Program

Introduction

Anthracnose is a turf disease found most often on intensely managed annual bluegrass or bentgrass. At least 13 warm and cool season grasses are known to be hosts for this disease. Environmental stresses such as drought and heat make the turf more susceptible during the mid-summer months. Both cultural practices and fungicide treatment can help to mitigate this disease. The following describes the disease and how to identify and manage it.

Cause, Hosts, and Occurrence

Cause: Colletotrichum cereale (formerly Colletotrichum graminicola)

Primary Hosts: Annual bluegrass, Creeping bentgrass; most warm and cool season grasses can be a host.

Occurrence: July-August

Key Symptoms

• Irregularly shaped patches of yellow-bronze turf. May also have a reddish cast in the area (Figure 1).
• Elongated, reddish-brown spots on the leaves (Figure 2).
• Infection of the lower stem of shoots (basal rot) can result in the death of tillers and browning of lower leaves.
  
• Black, spiny fungal fruiting structures (acervuli) on infected leaves, visible with a 10X hand lens.

Figure 1. Anthracnose on bentgrass. Note the overall bronze color and dying tillers. (Photo courtesy of G.W. Wilson, Bugwood.org)
		Figure 2. Fruiting structures of the anthracnose fungus (setae of the acervuli), which are visible with a 10X hand lens.* *Figure 2 reproduced with permission from D. Settle, A. Martinez-Espinoza, L. Burpee. 2006. Anthracnose of Turfgrass. The Plant Health Instructor. OI:10.1094/PHI-I-2006-1205-01) Photographer, J. Kaminski.

Cultural/Maintenance Practices

• Provide sufficient nitrogen to maintain a moderate growth rate through the summer.
  
• Irrigate to maintain plant vigor and avoid drought stress.
  
• Compaction and thatch should be managed to reduce stresses.

Fungicide Program

Fungicides for anthracnose management are listed in Table I. Preventive spray programs have typically been more effective than curative programs for this disease. Product examples are provided for each active ingredient, but not all products are listed. Homeowner and commercial product labels will provide a list of active ingredients.

While the active ingredient may be in combination with others, users should look for a specific active ingredient with or without other chemistry modes of action.

Fungicides listed represent the best information available. Read and follow all product label directions for mixing and application.

This publication has been peer reviewed.