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Ralstonia solanacearum is a bacterium that causes wilt diseases in plants. It is not harmful to humans or animals. Worldwide, there are five known races of R. solanacearum. Races 2, 3, 4, and 5 are not known to occur in the United States. Race 1 is endemic to the southeastern United States where it can affect crops, such as tomato.

USDA considers R. solanacearum to be a select agent because the pathogen has the potential to pose a severe threat to plant health. Determining the specific race and biovar can only be done through advanced molecular testing that must be conducted by APHIS because of Select Agent Regulations. Race 3 biovar 2 causes diseases such as brown rot of potato, bacterial wilt of tomato and eggplant, and southern wilt of geranium

In April 2020, APHIS confirmed the detection of R. solanacearum race 3 biovar 2 in a U.S. greenhouse that had purchased geranium cuttings from an offshore production facility.  This is the first confirmed detection of this pathogen in a U.S. greenhouse since 2004. APHIS has successfully eradicated all previous detections of this pathogen in U.S. greenhouses and is working to eradicate the current incursion. 

The links below provide information about the pest status of Ralstonia solanacearum, the Federal Select Agent Program, and regulations. 

In 2007, APHIS implemented a certification program for geraniums imported to the United States. The program requires specific clean-culture practices and regular testing in offshore greenhouses. Shipments must also be accompanied by a phytosanitary certificate with an additional declaration attesting that the geraniums have been tested and are free of R. solanacearum race 3 biovar 2.

Lynn Evans-Goldner
National Policy Manager
Telephone: 301-851-2286

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