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Publication #SS-PLP-56

Anthracnose1

M. L. Elliott and P. F. Harmon2

Anthracnose

Pathogen: Colletotrichum graminicola

Turfgrasses Affected: Primarily centipedegrass, but it is known to occur on all warm-season turfgrasses.

Occurrence: This disease primarily affects centipedegrass. It is normally observed in the spring during periods of high moisture (rain or heavy fog) and warm temperatures. Disease severity is often greater on stressed turfgrass, especially during springs that follow cold winters.

Symptoms/Signs: Leaf infection appears as reddish-brown to brown spots that are often surrounded by a narrow yellow halo. Single spots may span the blade width, causing leaf yellowing and death. Tiller infection results in stem death and the development of small, yellow patches of turfgrass (Figure 1).

Figure 1. 

Anthracnose symptoms on centipedegrass.


Credit: G. W. Simone
[Click thumbnail to enlarge.]

The fungus can be observed with a hand lens. It appears as small, black, cushion-like structures (acervuli) with black spines (setae) extending from the cushion. These structures are found at the base of leaves next to the stem.

Cultural Controls: Avoid potassium deficiency. Do not apply excessive nitrogen during potential disease development periods. Do not use readily available forms of nitrogen, such as soluble liquids or quick-release nitrogen sources, just prior to or during these periods. Instead, use slow-release nitrogen sources. Apply a balanced fertilizer containing equivalent amounts of potassium and nitrogen, preferably a slow-release potassium form. Avoid drought stress. Irrigate to saturate the root zone. Irrigate only in the early morning hours (between 2:00 and 8:00 a.m.) when dew is already present. If the diseased areas are associated with compacted soils, alleviate the compaction. If thatch is excessive, renovate.

Chemical Controls: Azoxystrobin, chlorothalonil, fenarimol, fludioxonil, metconazole, myclobutanil, propiconazole, thiophanate methyl, triadimefon, trifloxystrobin, and triticonazole

For a homeowner's guide to turfgrass fungicides, see http://edis.ifas.ufl.edu/document_pp154. Check fungicide labels for site application restrictions, as some fungicides cannot be used on residential lawns. Follow label directions and restrictions for all pesticides. The presence of a fungicide on this list does not constitute a recommendation.

Refer to the "Turfgrass Disease Management" section of the Florida Lawn Handbook (http://edis.ifas.ufl.edu/lh040) for explanations of cultural and chemical controls.

Footnotes

1.

This document is SS-PLP-56, one of a series of the Plant Pathology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date April 2001. Revised February 2011. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

M. L. Elliott, professor, Plant Pathology, Fort Lauderdale Research and Education Center; and P. F. Harmon, associate professor, Plant Pathology Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.