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International Society for Infectious Diseases
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Date: February 2025
Source: European & Mediterranean Plant Protection Organisation (EPPO) Reporting Service 02/2025/047 [edited]
https://gd.eppo.int/reporting/article-8059


_Clavibacter nebraskensis_ causes Goss's wilt and leaf blight of maize (_Zea mays_). The bacterium was detected in several localities in 4 provinces in South Africa. Samples collected from maize farms in Free State, North-West and Gauteng provinces were tested using molecular techniques. The disease was also reported in the Eastern Cape through visual inspections.

Surveys in other parts of the country are being conducted. No further detections have occurred so far. Phytosanitary measures are being implemented in the affected farms. The Department of Agriculture, Land Reform and Rural Development is continuing with research to understand the epidemiology and management of the pest to support local maize producers while conducting delimiting surveys to determine the extent of the spread of the disease.

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Communicated by:
ProMED

[Goss's wilt (GW) and blight of maize (_Zea mays_) is caused by the bacterium _Clavibacter nebraskensis_. It is a persistent and economically serious disease of susceptible maize hybrids. Some secondary hosts such as sorghums, sugar cane and several grasses have been reported and may serve as pathogen reservoirs.

Symptoms may include systemic wilting of plants; lesions, blighting and necrosis on leaves; reduction of ear size; and death of plants. Infection of leaves, stems and roots occurs primarily through wounds (mechanical, hail or insect damage); plants are susceptible at all growth stages. The pathogen is seed transmitted and overwinters on crop debris and maize kernels. Disease management includes cultural practices to minimise inoculum, crop rotation and use of resistant or tolerant crop varieties. A recent increased rate of spread in North America has been suspected to be due to an emerging new strain (see ProMED post 20110921.2865).

The report in South Africa is the first report of GW outside the Americas. It would be important to identify the source of the initial infection and the route of the apparent spread in the country to prevent further incursions. The pathogen as now been added to the EPPO alert list.

Pictures
Goss's wilt symptoms on maize:
https://c8.alamy.com/comp/2GGP2P8/gosss-bacterial-wilt-clavibacter-michiganensis-severe-necroses-lesions-of-upper-leaves-on-maize-or-corn-plant-usa-2GGP2P8.jpg,
https://plantwiseplusknowledgebank.org/cms/10.1079/pwkb.species.15339/asset/bb88914f-b150-49ea-af87-77d56f1f62fd/assets/graphic/15339_04.jpg,
https://www.tandfonline.com/cms/asset/35acb613-0f94-46e0-9ecc-a293f83b164c/tcjp_a_1506502_f0001_c.jpg,
https://bsppjournals.onlinelibrary.wiley.com/cms/asset/036c7fb4-8708-4364-8710-09078af44595/mpp13268-toc-0001-m.jpg?trick=1702627544746 and
https://www.pioneer.com/CMRoot/pioneer/US/images/agronomy/library_corn/diseases/wilt/goss_wilt_symptoms_2.jpg (vascular discolouration)

Links
_C. nebraskensis_ addition to EPPO alert list:
https://gd.eppo.int/reporting/article-8060 and via
https://www.eppo.int/ACTIVITIES/plant_quarantine/alert_list
Country notification to the International Plant Protection Convention (IPPC):
https://www.ippc.int/fr/countries/south-africa/pestreports/2025/01/notification-on-the-detection-of-clavibacter-michiganensis-subsp-nebraskensis-goss-wilt-on-maize-in-the-republic-of-south-africa/
IPPC alert:
https://www.ippc.int/en/news/ippc-pest-alert-first-detection-of-clavibacter-nebraskensis-outside-north-america/ and via
https://www.ippc.int/en/core-activities/capacity-development/programmes/strenghtening-pest-outbreak-alert-and-response-systems/pest-alerts/
Information on Goss's wilt:
https://gd.eppo.int/taxon/CORBNE/ (incl. host range),
https://doi.org/10.1079/pwkb.species.15339 (with pictures),
https://extensionpubs.unl.edu/publication/g1675/2006/pdf/view/g1675-2006.pdf,
https://www.pioneer.com/us/agronomy/goss_wilt_cropfocus.html (with disease cycle),
https://www.extension.purdue.edu/extmedia/bp/BP-81-W.pdf and
https://doi.org/10.1111/mpp.13268 (review)
GW disease cycle:
https://bsppjournals.onlinelibrary.wiley.com/cms/asset/4cca80f1-dc1c-400c-8616-bec8d66cd565/mpp13268-fig-0003-m.jpg
_C. nebraskensis_ taxonomy and synonyms:
https://www.uniprot.org/taxonomy/31963
- Mod.DHA

ProMED map:
South Africa: https://promedmail.org/promed-post?place=8722675,179]

See Also

2013
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Goss's wilt, maize - USA (02): (LA) conf 20130925.1966211
Goss's wilt, maize - USA: (LA) susp. 20130709.1814416
2011
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Goss's wilt, maize - USA: new strain susp. 20110921.2865
2010
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Goss's wilt, maize - Canada: 1st rep (MB) 20100820.2901
Goss's wilt, maize - USA: (MN) 20100215.0529
2009
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Bacterial diseases, maize, sorghum - USA: (NE) 20090713.2500
2008
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Goss's wilt, maize - USA 20080822.2612

Website: http://www.isid.org

Published: March 10, 2025