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Publication #SSAGR203

Sugarcane Eyespot Disease1

P. Rott, J. C. Comstock, R. A. Gilbert, and H. S. Sandhu2

Eyespot has been reported in many sugarcane-growing areas of the world. Eye spot is a minor disease because almost all varieties are resistant, even without any selection or screening program for resistance. A rare susceptible variety may have severe economic losses if environmental conditions are favorable. In one case, a 33% loss in cane tonnage was documented in Mexico when yields of diseased plots were compared with disease-free plots. Eyespot was observed in a few growers' fields in 2004, but it is not a problem for Florida growers at this time, thus only the most important features of the disease will be described.

Symptoms

The first observable symptoms are minute water-soaked spots that usually occur on young leaves. Typical mature eyespot symptoms are characterized by a reddish-brown elliptical lesion (0.5–4.0 mm long, 0.5–2.0 mm wide) with yellowish-brown margins (Figure 1). Reddish-brown to yellowish-brown streaks, sometimes called "runners," extend upward from individual lesions toward the leaf tip. These streaks are 3–6 mm wide and 30–90 cm long. Multiple lesions can be extensive. The runners occur only in cooler temperatures and are not present in hotter temperatures (Figure 2). The runners are the results of tissue damage caused by a toxin produced by the pathogen.

Figure 1. 

Eyespot lesion and runner on a sugarcane leaf


Credit:

Philippe Rott, UF/IFAS


[Click thumbnail to enlarge.]

Figure 2. 

Multiple eyespot lesions with runners in the field


Credit:

Philippe Rott, UF/IFAS


[Click thumbnail to enlarge.]

Causal Agent

Eyespot disease is caused by the fungus Bipolaris sacchari. No information is available regarding variation in pathogenicity of the pathogen.

Spread of the Disease

Eyespot is transmitted by spores (conidia), which are produced abundantly on leaf lesions and are dispersed by wind and rain. Fungal spore germination is favored by high humidity and dew formation. Colonization is more rapid in younger leaves than older leaves. Transmission by seed piece does not occur. Mechanical transmission by equipment and by human activity is not an issue.

Prevention and Control

The only practical and efficient method for controlling eyespot disease is the use of resistant sugarcane clones. Resistant clones can be grown without losses, even in environments that favor eyespot disease. Chemical control using foliar fungicides is not practical.

Footnotes

1.

This document is SS-AGR-203, one of a series of the Agronomy Department, UF/IFAS Extension. First printed March 1991. Revised February 2014. This publication is also a part of the Florida Sugarcane Handbook, an electronic publication of the Agronomy Department. For more information you may contact the editor of the Sugarcane Handbook, R.W. Rice (rwr@ufl.edu). Please visit the EDIS Web site at http://edis.ifas.ufl.edu.

2.

P. Rott, professor, Everglades Research and Education Center, Belle Glade, FL; J. C. Comstock, research plant pathologist, USDA-ARS, Sugarcane Field Station, Canal Point, FL; R. A. Gilbert, professor and Agronomy chair, Gainesville, FL; and H. S. Sandhu, assistant professor, Everglades Research and Education Center, UF/IFAS Extension, Gainesville, FL 32611.

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitable composition.


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.