Ralstonia Solanacearum Found in New York Greenhouse

Plant Protection and Quarantine

January 21, 2004

Recent detections of Ralstonia solanacearum race 3 biovar 2, in December 2003, have been traced to an importer of geraniums from Guatemala. In response to the recent detections, the U.S. Department of Agriculture‘s (USDA) Animal and Plant Health Inspection Service (APHIS) has temporarily suspended imports of geraniums from one producer in Guatemala. APHIS will not lift the import ban, until it inspects the affected facilities and specifies future preventative measures to be implemented.

The disease was found in two varieties of geraniums—Americana Coral and Americana Bright Red. A third variety, Americana Cherry Rose II, is implicated because it was produced in the same vicinity in Guatemala as the two varieties that tested positive. More than 400 customers have received the potentially infected varieties. Customers that have purchased affected varieties from Guatemala are encouraged to monitor potentially affected plants for wilt and to report any symptoms to their local State Plant Health Director(SPHD) .

In cooperation with the importer of the affected plants, APHIS is actively tracing the whereabouts of the suspect material. APHIS’ priority is to locate, evaluate, and destroy, if necessary, infected plant material.

Ralstonia solanacearum race 3 biovar 2, a bacterial pathogen, poses a significant threat to the flower and potato industries. While other races of Ralstonia solanacearum exist in the United States, Ralstonia solanacearum race 3 biovar 2 is newly detected in this country. Ralstonia solanacearum race 3 biovar 2 was first officially confirmed by APHIS in imported geraniums in the United States in February 2003, and was eradicated.

Ralstonia solanacearum race 3 biovar 2 is known to infect ornamental plants (e.g., geraniums) and several important agricultural crops (e.g., tomatoes, eggplants, peppers, and potatoes). Plants infected with Ralstonia solanacearum develop yellowing,
wilting, and browning of the lower leaves. In geraniums, the symptoms of Ralstonia solanacearum may be confused with bacterial blight caused by Xanthomonas pelargonii. Both diseases cause the infected plants to wilt. Bacterial blight also causes leaf spots, which Ralstonia solanacearum does not.

Ralstonia solanacearum is transmitted especially well in water and soil, as well as through certain greenhouse practices. The disease is spread very easily by transplanting infected plants and propagative material. Pruning and grafting without disinfecting associated equipment between plants may also facilitate spread of the disease.

In potatoes, Ralstonia solanacearum race 3 biovar 2 causes bacterial wilt, which has severely limited crop production in parts of Asia, Africa, and South and Central America, where it has occurred. Bacterial wilt is one of the most destructive diseases of potatoes.

Note to stakeholders: Stakeholder announcements and other APHIS information are available on the Internet. Access the APHIS home page by pointing your Web browser to http://www.aphis.usda.gov. For additional information on this topic, contact Dore Mobley at (301) 734–7255 or dore.m.mobley@aphis.usda.gov. In addition, PPQ has a SPHD located in nearly every state. SPHD office phone numbers are normally listed in the local phone directory under the Federal government
listings. SPHDs can provide additional information on Ralstonia solanacearum race 3 biovar 2.

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