University of Nebraska-Lincoln Extension, Institute of Agriculture and Natural Resources

August 11, 2006

Goss’s wilt and blight reported in western Nebraska

Figure 1. Goss's wilt on a corn leaf.
(IANR Photo by Tamra Jackson)
Several suspected cases of Goss’s wilt and blight of corn have been reported in the Panhandle and near North Platte. Goss’s wilt is caused by the bacterium Clavibacter michiganensis subsp. nebraskensis.

Foliar lesions are often dark green and water-soaked and are similar in appearance to those associated with Stewart’s disease. Small dark green freckles can develop at the edges of some developing lesions and mature lesions are frequently shiny and orange discolored because of the secretion of bacterial exudate onto the surface of the leaf, both of which aid in identification (Figure 1). The pathogen is the only gram positive bacterium known to infect corn, so this test and other enzyme tests have been used for preliminary identification in samples collected this year in western Nebraska.

Infection by this bacterium requires injury to the plant and is most common in Nebraska following hail, high winds, and sandblasting. Infection also can be systemic and cause the vascular bundles inside cut stalks to be discolored orange. The optimal temperature for disease development is 80°F; the pathogen will die at temperatures over 100°F.

The most susceptible hybrids can sustain yield losses of over 50% with severe infections. Resistant dent corn hybrids are available and are recommended for management in areas where the disease is severe. Resistance is controlled by more than one gene and the effect is additive, determined by how many are present in the plant. In Nebraska, less than 25% of seed companies (5 out of an incomplete list made up of 22 companies) provide ratings for how their hybrids react to Goss’s wilt. In addition to planting resistant hybrids, disease risk can be reduced by rotating out of corn and by using tillage practices that reduce plant debris on the soil surface where the pathogen overwinters.

Tamra Jackson
Extension Plant Pathologist — Lincoln
Bob Harveson
Extension Plant Pathologist
Panhandle Research and Extension Center

You've got mail!
To receive Email notification when the latest Crop Watch is posted to the Web, use this form.

Copyright 2006 by the University of Nebraska Board of Regents. All rights reserved.
Published by University of Nebraska-Lincoln Extension in the Institute of Agriculture and Natural Resources Cooperating with the counties and the U.S. Department of Agriculture.
The University of Nebraska-Lincoln does not discriminate on the basis of gender, age, disability, race, color, religion, marital status, veteran's status, national or ethnic origin, or sexual orientation.