Jan 30, 2004

Ralstonia To-DateSource: APHIS, SAF and Goldsmith Plants

Since the Ralstonia announcement was made about a month ago, there has been so much information floating around about the outbreak that no one really knows what is going on with the disease at this point. Well, we have figured out some of it and are here to tell you the latest information that is going on to date. We have spoken to Lin Schamle from SAF, Dore Mobley from APHIS and Richard Goldsmith who consulted with his production manager Don Snow about the following information, and everyone seems convinced that the following is true at this time. While the main structure of the following events might already be common knowledge, many of the specifics are just now coming to light.

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According to a document from APHIS, the Plant Protection and Quarantine (PPQ) Center for Plant Health Science and Technology laboratory in Beltsville, Md., confirmed the presence of Ralstonia solanacearum race 3 biovar 2 in geraniums from one commercial greenhouse in New York State, in rooted cuttings of ‘Americana Coral’ on December 31, 2003 and in direct-ship material of ‘Americana Bright Red’ on January 2, 2004. The greenhouse had received both varieties of infected propagative material from the Goldsmith Plants, Inc. facilities located in Guatemala. The rooted plants (Americana Coral) were received via Glass Corners Greenhouse in Michigan. The third suspect variety, ‘Americana Cherry Rose II’, was implicated and held because it was grown in the same greenhouse with the two other suspect varieties.

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Based on the positive findings, Goldsmith Plants, Inc. had voluntarily quarantined its Guatemalan greenhouses, and suspended shipments of geranium cuttings. On January 6, 2004, APHIS notified Goldsmith Plants that further importations of geranium cuttings from the suspect Guatemala facility would be prohibited until further notice.

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During the week of January 5, the PPQ and its state partners began issuing emergency action notices to potentially affected facilities, based on a list that Goldsmith Plants provided, and initiated an eradication program. Eradication efforts began with the four rooting stations: Glass Corner Greenhouse, Grand Rapids, Mich.; Rakers Acres, Litchfield, Mich.; Speedling, Blairsville, Ga; and Pacific Growers, Blaine, Wash. It is estimated that 400,000 plants were destroyed between the four rooting stations.

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During the week of January 12, the PPQ continued to hold potentially infected plants but put a temporary moratorium on their destruction pending the results of a site visit to the suspect production facility in Guatemala. In Guatemala, scientists found wilted plants among two of the three suspect varieties at several locations in one greenhouse. They confirmed the presence of Ralstonia sp. (not Ralstonia solanacearum race 3 biovar 2) in samples from these plants with two different serologically based tests. Confirmation of Ralstonia in the Guatemalan samples to the target race and biovar was later received on January 23, 2004, confirming that an Americana Bright Red did in fact have Ralstonia solanacearum race 3 biovar 2.

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Based on the findings in Guatemala, PPQ reinstated the destruction order for the three suspect varieties and other potentially exposed plants that were shipped from Guatemala between July 27, 2003 and January 3, 2004. As of January 26, 2004, APHIS estimates that 459 facilities in 41 states have received suspect geraniums; 362 facilities are on hold, 79 control actions have been initiated, 68 facilities have been released, and 529, 367 plants have been destroyed. Current estimates are that between 1.5 and 2 million cuttings/plants will be destroyed.

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Richard Goldsmith said that APHIS is meeting early this week to discuss the next steps and additional test results if they become final. He says that if all goes well, AHPIS may be ready to allow the Goldsmith Plants’ Guatemalan facility to commence with production as soon as later this week.

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USDA is diligently working, with Goldsmith’s cooperation, to develop a water effluent (waste water) testing system to quickly and accurately determine the presence or absence of R. solanacearum in a greenhouse. This system may be available for use in offshore geranium production facilities in the near future, but it will require further testing and development before it can be used in U.S. greenhouses because of different soils/media and watering systems.

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According to Lin Schmale, “Beyond the obvious significance, this test is important because the research was funded through the Floriculture and Nursery Research Initiative, from USDA-ARS (Agricultural Research Service) dollars. The Initiative is an effort that SAF and the American and Nursery and Landscape Association have worked on for many years, and the industry has lobbied Congress for dollars to go towards efforts that will benefit the floral and nursery industry. Because of our close working relationship with ARS, we were able to put some of the Initiative money, last year, into a research project by Dr. Caitilyn Allen, University of Wisconsin, which almost immediately came up with several answers to previously unanswered scientific questions — and has led to this water effluent testing protocol.

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Growing practices are very important in a situation like this, commercial growers in the U.S. need to help protect themselves in the event of any disease introduction — but particularly Ralstonia, One thing to remember is that any grower who has Federal Crop Insurance may be covered on this issue (it depends on the state and the particular policy) but that you must contact your agent before destruction occurs. Here is a list of sanitation practices that would be beneficial towards keeping your greenhouse disease free:

• Do not use sub-irrigation or shared watering systems;
• Use strict sanitary practices when handling or propagating plants;
• Maintain varieties of geraniums from foreign sources separately;
• Do not hang baskets of geraniums over other crops;
• Do not grow geraniums on the ground or on the kind of plastic sheeting or other surface that would allow water to spread from one pot to another;
• Disinfect water systems and regularly treat irrigation water from any source; and
• Keep greenhouses, areas around greenhouses and irrigation water holding or overflow ponds free of weeds.

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This information came from the APHIS Action Guide http://www.aphis.usda.gov/ppq/ep/ralstonia/rasltoniaactionplanv4web.pdf

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SAF and ANLA also have a “Quick Guide” that is an informational and precautionary piece for growers about Ralstonia. For a more in-depth look go to www.safnow.org or www.anla.org.