An Overview of Goss's Bacterial Wilt and Blight

***Updated in 2025, this version replaces the previous An Overview of Goss's Bacterial Wilt and Blight (Archived) publication.***

Goss’s bacterial wilt and blight of corn is an economically important disease of susceptible dent and specialty corn hybrids. This disease (most commonly called Goss’s wilt) is caused by the bacterium Clavibacter nebraskensis. Grain yield losses from Goss’s wilt can be severe, exceeding 50%.

Goss’s wilt was first observed in south-central Nebraska in 1969 and was subsequently reported in neighboring states. The disease’s prevalence was low throughout the region from the 1980s through the early 2000s. However, between 2006 and 2017, Goss’s wilt reemerged in these states and was reported in many other U.S. states and two Canadian provinces.

Currently, the known distribution of Goss’s wilt in the U.S and Canada reaches from Indiana in the east to Colorado in the west, and from Manitoba and Alberta in the north to Texas in the south. More recently, Goss’s wilt was reported in Mexico (2023) and South Africa (2024). These are the first reports of Goss’s wilt outside of the U.S. and Canada.

This publication describes Goss’s bacterial wilt and blight symptoms, describes disorders commonly confused with the disease, and summarizes management strategies.

Symptoms

Goss’s wilt can cause leaf blight and systemic wilt symptoms. Leaf blight is the most common symptom and may occur at any growth stage. Leaf symptoms often develop from the leaf tips or in association with wounding caused by hail, sandblasting, and additional types of injury. Young lesions appear as streaks of light green tissue with water-soaking on the leaf (Figure 1). Mature leaf lesions are elongated, tan to grayish-brown, and have irregular or wavy margins that extend parallel to the veins (Figure 2). The tan lesions can coalesce to affect large sections of leaf area, killing more than 60% of the leaf area on infected plants (Figure 3).

Dark green to black, scattered, discontinuous water-soaked spots (“freckles”) develop within the plant tissue inside the lesions and are diagnostic for Goss’s wilt (Figures 2 and 4). The freckles appear translucent when they are backlit. In humid conditions, small, orange droplets of bacterial ooze may be observed on the lesions. When dried, this ooze may appear shiny and similar to dried varnish (Figure 5).

The systemic wilt phase is less common than the leaf blight phase and is often first observed in the early vegetative stages of growth (corn growth stages V2-V6). When the wilt phase develops, the infection may discolor xylem elements or cause a slimy stalk rot, which is followed by wilting and plant death (Figures 6-8). Plants that become systemically infected later in the growing season may wilt and appear drought stressed. These plants can also have weak stalks and increased susceptibility to lodging due to wind or other stress.

Disease Cycle

The Goss’s wilt pathogen, Clavibacter nebraskensis, overwinters in infested corn residue on or near the soil surface, which serves as the primary source of inoculum (Figure 9). Infested residue may allow the pathogen to survive on the soil surface for at least 10 to 15 months. Burying infested residue reduces the pathogen’s survival. With that said, conservation tillage should not be abandoned in areas where it is a critical tool for soil management.

The Goss’s wilt pathogen can also survive in additional plant species. Confirmed hosts include grain sorghum, annual ryegrass, sudangrass, several foxtail species, johnsongrass, large crabgrass, shattercane, big bluestem, little bluestem, and woolly cupgrass. These and several additional grass species grown alone or in cover crop mixes may serve as sources of inoculum that can infect corn.

The bacterium is likely splashed from infested residue or grasses onto the surface of corn leaves. The disease typically develops after the bacterium enters wounds in leaves caused by hail, blown sand/soil, or wind. However, wounds may not be required for infection, and infection can occur through hydathodes at the tips of corn leaves.

The bacterium can spread short distances within a field by leaf contact between adjacent plants and by aerial dispersal between fields across country roads during the growing season. In addition, equipment can spread infested leaves or other plant material from field to field. Seed can be infested at low levels and is not known to be an important means of dissemination; however, it may play a role in introducing the pathogen into new areas or specific sites within fields.

Infection may occur at any growth stage. Infection prior to V6 often results in systemic infections that lead to plant death and stand loss. Infections after V6 result in leaf blight. Symptoms often become most visible and severe after silking (R1 growth stage).

Conditions that Favor Disease

Planting hybrids susceptible to Goss’s wilt, practicing reduced tillage, and planting corn continuously in fields with a history of the disease can increase the likelihood of outbreaks of Goss’s wilt. Strong storms, wind, sandblasting, and hail that injure corn leaves allow the pathogen to enter and infect the plant in situations where inoculum is present.

Disease development is favored by warm (80°F/27°C) weather. High (greater than 95°F/35°C) or cool (less than 70°F/21°C) temperatures may impede disease development. The disease may occur and spread in fields regardless of irrigation practices, although irrigation enhances disease progression.

Yield Loss and Impact

Many states and provinces have documented yield losses in susceptible corn hybrids with the leaf blight phases of the disease. Early infection can result in large yield losses. For example,  plants infected during vegetative growth stages can experience yield losses of more than 50%. No hybrids are completely resistant (immune) to Goss’s wilt, but yield losses for resistant hybrids are significantly reduced compared to susceptible cultivars (Figure 10).

Diagnosis 

Goss’s wilt can be confused with several other diseases. Therefore, we recommend that you have a diagnostic laboratory confirm suspected samples. Confirming the presence of the pathogen through observance of characteristic symptoms, signs, and bacterial streaming of lesions aids in accurate diagnosis (Figure 11).

Diseases and Other Conditions with Similar Symptoms

Northern Corn Leaf Blight (Exserohilum turcicum)

Corn with symptoms of northern corn leaf blight (NCLB) typically has canoe- or cigar-shaped lesions that are 1 to 4 inches long and 1⁄2- to 1-inch wide (Figure 12). The lesions initially have grayish-green margins. Eventually, typical NCLB lesions turn tan and contain dark areas of fungal sporulation when mature. 

How to distinguish northern corn leaf blight from Goss’s wilt: NCLB can be distinguished from Goss’s wilt by the lesion’s canoe shape and even lesion margins. NCLB lesions lack the freckles in the lesions and bacterial streaming observed in Goss’s wilt. On some hybrids, lesions of NCLB may have discoloration around the edges that can resemble freckling, but close observation of the lesions will not reveal the classic freckles and bacterial ooze associated with Goss’s wilt (Figure 13). In recent years, an increase in NCLB incidence in some areas and reduction in the number of corn hybrids that produce the recognizable “freckles” symptom of Goss’s wilt has made differentiating these two diseases more challenging, often requiring additional testing.

Stewart’s Bacterial Wilt (Pantoea stewartii)

Both Goss’s wilt and Stewart’s wilt may cause seedling blights that kill young plants (Figure 14). Leaf lesions are also similar in that they can both develop into long lesions with wavy margins that extend between veins.

How to distinguish Stewart’s bacterial wilt from Goss’s wilt: A key distinguishing characteristic of Goss’s wilt is the dark green to black freckles that can develop within the lesions. If you suspect Stewart’s wilt, a sample should be sent to a diagnostic clinic as this disease has rarely been documented since the early 2000s, and is not as widely distributed as Goss’s wilt.

Bacterial Leaf Streak (Xanthomonas vasicola pv. vasculorum)

Bacterial leaf streak appears most common in the western Corn Belt and into Iowa and Minnesota. Although this is a bacterial disease, the symptoms appear more like gray leaf spot than Goss’s wilt (Figure 15).

How to distinguish BLS from Goss’s wilt: Bacterial leaf streak produces narrow tan to yellow lesions and streaks on leaves. They are narrower than Goss’s wilt lesions, but can be small (less than 1 inch) to several inches long. When backlit, bacterial leaf streak lesions often appear bright yellow. The freckles that develop in Goss’s wilt lesions are a diagnostic characteristic and do not develop in bacterial leaf streak lesions. Bacterial streaming can be observed with both bacterial leaf streak and Goss’s wilt.

Diplodia Leaf Streak (Stenocarpella macrospora)

Mature Diplodia leaf streak lesions are long and slender, parallel to the veins, and taper at the ends (Figure 16).

How to distinguish Diplodia leaf streak from Goss’s wilt: Diplodia leaf streak lesions are distinct based on the bright yellow halos around lesions. These lesions also have dark fungal structures (pycnidia) that appear as pepper-like specks. Unlike Goss’s wilt, Diplodia lesions do not have bacterial streaming or dark, water-soaked freckles.

Nutrient Deficiencies

Nitrogen, potassium, or phosphorus deficiencies can sometimes be confused with Goss’s wilt. However, the presence of nutrient deficiency symptoms may differ based on the plant’s general growth stage.

How to distinguish nutrient deficiencies from Goss’s wilt: The general symptoms associated with nutrient deficiencies do not include the water-soaked freckles, shiny bacterial ooze, or the bacterial streaming characteristic of Goss’s wilt lesions (Figure 17).

Drought Stress/Leaf Scorch

High temperatures and drought stress can cause brown discoloration and kill leaf tissues, often from the margins inward (Figure 18).

How to distinguish drought stress/leaf scorch from Goss’s wilt: The brown discoloration from leaf scorch tends to be more uniform in color, and the necrotic leaf tissues do not have the water-soaked freckles, shiny bacterial ooze, or bacterial streaming in the lesions associated with Goss’s wilt.

Disease Management

The best way to manage Goss’s wilt is to plant highly resistant corn hybrids. Additional control can be achieved by rotating crops with non-hosts (such as soybean, dry bean, small grains, or alfalfa) to help reduce the primary inoculum for the subsequent corn crop.

Because the bacterial pathogen survives in infested residue, tillage that buries residue may reduce the presence of inoculum; however, it should not be used if conservation tillage is a top priority. It may also be beneficial (where feasible) to control grassy weed hosts and practice tillage that buries infected residue after harvest. Fungicides are ineffective, and other chemical sprays have not consistently been effective in reducing symptoms or preserving yield.

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Acknowledgments

Authors

Dean Malvick, University of Minnesota; Tamra Jackson-Ziems, University of Nebraska-Lincoln; and Alison Robertson, Iowa State University.

Reviewers

Daisy Ahumada, North Carolina State University; Tom Allen, Mississippi State University; Gary Bergstrom, Cornell University; Alyssa Betts, University of Delaware; Mandy Bish, University of Missouri; Kaitlyn Bissonnette, University of Missouri; Carl Bradley, University of Kentucky; Emmanuel Byamukama, South Dakota State University; Martin Chilvers, Michigan State University; Alyssa Collins, Pennsylvania State University; Maira Duffeck, Oklahoma State University; Paul Esker, Pennsylvania State University; Travis Faske, University of Arkansas; Andrew Friskop, North Dakota State University; Austin Hagan, Auburn University; Doug Jardine, Kansas State University; Shelly Pate Kerns, Louisiana State University AgCenter; Nathan Kleczewski, University of Illinois; Daren Mueller, Iowa State University; Pierce Paul, The Ohio State University; Madalyn Shires, South Dakota State University; Adam Sisson, Iowa State University; Damon Smith, University of Wisconsin-Madison; Darcy Telenko, Purdue University; Albert Tenuta, Ontario Ministry of Agriculture, Food and Agribusiness; Lindsey Thiessen, North Carolina State University; and Kiersten Wise, University of Kentucky; and Yuan Zeng, Virginia Tech.

How to cite: Crop Protection Network. 2025. An Overview of Goss's Bacterial Wilt and Blight. Malvick, Dean; Jackson-Ziems, Tamra; Robertson, Alison. CPN-2010. DOI: doi.org/10.31274/cpn-20190620-003.