First confirmed report of Clavibacter nebraskensis outside North America

Date of Issue: 03/03/2025

Trigger alert event:

NRO: Pest report: Clavibacter nebraskensis (Goss's wilt of maize) has been detected in four provinces in South Africa

© Osdaghi, E., Robertson, A.E., Jackson-Ziems, T.A., Abachi, H., Li, X., & Harveson, R.M., 2022. Licensed under CC 4.0. Clavibacter nebraskensis causing Goss's wilt of maize, 2024

Distribution*:

Africa: South Africa.
North America: Canada, Mexico, United States of America (EPPO Global Database).

Major economic host:

Maize (Eichenlaub, R., & Gartemann, 2011; Lang et al., 2017).

Current impact:

Severe infections have been documented to cause yield losses of up to 50% in susceptible maize varieties, especially under favorable environmental conditions such as high humidity and warm temperatures (Jackson-Ziems et al., 2014). Between 2012 and 2015, estimated total yield losses due to Goss’s Wilt in the U.S. and Canada exceeded 1.27 million tonnes, making it one of the most destructive maize diseases in the northern U.S. and Ontario (Wise et al., 2019).

Environmental conditions favoring spread:

The pathogen thrives in warm temperatures and high humidity, which are common in maize-growing regions (Wise et al., 2019).

Possible pathways of spread for Clavibacter nebraskensis:

The pathogen spreads through both natural and human-mediated pathways. Naturally, the pathogen can spread via wind-driven rain, contaminated soil, and infected crop residues, which serve as reservoirs for future infections. Human activities, such as the movement of contaminated agricultural equipment and the trade of infected plant material, facilitate long-distance spread. Seeds spreading is possible. However, the spreading rates of seeds are considered low (Flores-Lopez et al., 2024). The risk of these pathways needs to be carefully determined.

*Disclaimer:

IPPC Pest Alerts are news items obtained from public sources. They do not serve as official communication from the IPPC or FAO. The "IPPC Pest Alerts" is an early warning tool for potential emerging plant pests. In some cases, information within alerts is not confirmed with the corresponding National Plant Protection Organization. They are provided solely as an early warning to IPPC Contracting Parties and should be used with this disclaimer in mind.

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