History and Future of Goss’s Wilt
Discovery and Distribution
Key Points
 The increased adoption of
conservation tillage and
continuous corn production
are contributing factors to the
resurgence of Goss’s wilt.
 The disease is able to survive
on plant residue that remains
on the soil surface.
 Monsanto breeding efforts are
focused on developing new
corn products with improved
resistance to Goss’s wilt for all
geographies.
Goss’s wilt (Clavibacter michiganensis ssp. nebraskensis) was first identified in the
United States in1969 in Dawson County, Nebraska. The disease was initially named
leaf freckles and wilt because of the distinct leaf symptoms. By the end of the 1970s,
the disease had
spread to most of
Nebraska and areas
in Colorado, Kansas,
Iowa, and South
Dakota. Wyoming,
Illinois, Wisconsin,
and Minnesota had
reported occurrences
1969
by the early 1980s.
1970s
At present, the
1980s
disease has been
1990s
found in 18 states
2000s
and in Alberta,
2010s
Manitoba, and
Ontario, Canada
Figure 1. States and timeline of reported incidences of Goss’s wilt since first
(Figure 1).1,2
identification in 1969 (white star).
Cultural Change Supports Disease Development
Infected corn residue left on the soil surface is the source of primary inoculum for future infections. University of Nebraska plant
pathologists determined that inoculum could still be found on surface residue 8 months after harvest; however, the bacterium could
not be recovered from infected leaf debris buried 4 or 8 inches in the soil.3 The disease spreads when bacteria are transported to
new locations via movement with weather fronts, movement of infected corn debris, and/or movement of infected seed. However,
during the first few decades after Goss’s wilt was first discovered, predominant production practices which included clean fall
plowing initially prevented widespread outbreaks of the disease in many regions of the Corn Belt. The exception was in the western
Corn Belt where conservation tillage had become common practice and the disease was a significant problem. As the practice of
conservation tillage became more common throughout the Corn Belt, Goss’s wilt outbreaks became more prevalent because of the
survival of the bacteria on surface residue.
Pathogen, Host, and Environment
The occurrence of any crop disease depends on three factors: the pathogen, a suitable host, and a favorable environment. If any
element is not present or favorable, the disease is less likely to develop to severe levels. Time is sometimes added as a fourth factor
because most diseases require a length of time to increase. In the case of Goss’s wilt, corn is a suitable host. Although different
corn products have different levels of resistance or susceptibility to Goss’s wilt, no corn product is immune from infection. The
bacterial pathogen is found in infected debris and disseminated with wind and blowing rain. Thus, the favorable environmental
conditions include strong winds and splashing rain, especially conditions such as hail that cause wounds to plant tissues through
which the bacteria can infect. For Goss’s wilt, the fourth element, time, is very important relative to the degree of damage that may
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History and Future of Goss’s Wilt
result from infection. Plants infected early in the
season at vegetative growth stages can sustain
much greater damage than those infected during
reproductive growth stages.
Goss’s Wilt Identification
Distinguishing Goss’s wilt from other leaf
diseases can be difficult and may require
examination at a plant diagnostic clinic. Infected
leaves will have lesions that may appear water
soaked with wavy margins (Figure 2). Within the
lesions, dark specks or freckles should be
present. Lesions may be shiny and sticky due to
exudates from the bacterium (Figure 3). In plant
clinics, diseased tissue will be examined for
bacterial streaming by placing a cut portion of a
lesion in a drop of water on a microscope slide.
Figure 2. Goss’s wilt lesions can appear water soaked.
Figure 3. Infected leaf appearing
shiny because of the exudates.
Product Susceptibility
Channel® seed products vary in their tolerance to Goss’s wilt; therefore, growers should review the Channel seed guide and/or
consult with Channel Seedsman when selecting products. As a group, products targeted for the Great Plains may have better
resistance to Goss’s wilt than products targeted for the central and eastern Corn Belt because the frequency of the disease in the
west has eliminated the practical use of the most susceptible products. In other areas of the Corn Belt, products with a broader
range of reactions to Goss’s wilt are available because the disease has not been as prevalent in those regions.
Farmers should be aware of situations where Goss’s wilt has occurred in areas where it was previously uncommon, and if
necessary, seek additional information. These fields become ideal sources for the survival and future distribution of the Goss’s wilt
bacterium. The probability of Goss’s wilt increases when severe weather conditions necessary for infection occur and a susceptible
corn product is grown in that particular field. Severe occurrences of Goss’s wilt will likely continue until all commercial products
grown have increased levels of resistance, or agricultural practices such as crop rotation that reduce the source of inoculum in corn
debris are practiced.
What is Ahead?
Monsanto corn breeders have established large product screening nurseries throughout the Corn Belt to identify germplasm with
greater tolerance to the disease in all geographies. Multiple testing sites provide an opportunity for corn breeders to assess the
response of an individual corn product to Goss’s wilt under different environments and differing levels of disease severity. A Goss’s
wilt reaction is assigned to each product based on the testing response across all geographies. Marker assisted breeding methods
are also used by Monsanto breeders to enhance traditional selection for identification of tolerant corn germplasm. These methods
have enabled Monsanto breeders to develop new products with adequate levels of Goss’s wilt tolerance for growers in any area
where corn is grown.
Sources:
1
Jackson, T.A., Harveson, R.M., and Vidaver, A.K. 2007. Goss’s bacterial wilt and leaf blight of corn. NebGuide G1675. University of Nebraska-Lincoln Extension.
Distribution map of Clavibacter michiganensis subsp. nebraskensis. April 2000. Map No. 549. CAB International.
3
Schuster, M.L. 1975. Leaf freckles and wilt of corn incited by Corynebacterium nebraskense Schuster, Hoff, Mandel, Lazar, 1972. Research Bulletin 270. University of Nebraska-Lincoln.
2
Individual results may vary, and performance may vary from location to location and from year to year. This result may not be an indicator of results you may obtain as local growing, soil and
weather conditions may vary. Growers should evaluate data from multiple locations and years whenever possible.
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Work® are registered trademarks of Channel Bio, LLC. ©2015 Monsanto Company. 131209080240 020415CAM
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