Info Submitted by Mary McKellar, NEPDN Prepared January 2008

Southern Wilt of Geranium Why is this a problem? Ralstonia solanacearum Race 3 Biovar 2 is a bacterium that causes the following diseases: –Southern Wilt of Geranium –Brown Rot of Potato –Bacterial Wilt of Potato, Tomato and other Solanaceous crops World wide losses from potato crops are more than $950 million per year. This particular race and biovar of the pathogen is not established in the U.S. and is designated as a member of the Agricultural Bioterrorism Select Agent List.

Other Ralstonia solanacearum Races and Biovars RaceHost RangeGeographic Distribution Biovar 1WideAsia, Australia, Americas 3,4 1 2Banana Other Musa spp. Caribbean,Brazil Philippines 1 3Potato, some other Solanaceae, Geranium; Worldwide except US and Canada 2 4GingerAsia3,4 5MulberryChina5

Southern Wilt of Geranium Pathway into the U.S. Introduction into the U.S. has been through the importation of geranium cuttings obtained from production greenhouses located outside the country. Introduction of Rs R3B2 on geranium cuttings 2000 (Year) Race 3 commonly found throughout the world except for United States and Canada Introduction of Rs R3B2 on geranium cuttings 1999 No Reported Cases 2001 No Reported Cases 2002 Introduction on cuttings from Kenya, 127 greenhouses in 27 states 2003 Introduction on cuttings from Guatamala, no additional sites found 2004 Testing but no positives - Yet Photo Peggy Greb, USDA-ARS

Southern Wilt of Geranium What does it look like? Yellowing, wilting and browning of lower leaves Vascular discoloration and necrosis of the stem Brown discoloration of the roots Photos Margery Daughtrey, Cornell University,

Bacterial Ooze Bacterial streaming: cut stem or petiole placed in water should display cloud generated from bacterial streaming out of plant tissue Photo Margery Daughtrey, Cornell University, Photo David B. Langston, University of Georgia, Bacterial Streaming Southern Wilt of Geranium What does it look like?

Southern Wilt of Geranium Disease Transmission Contaminated soil, irrigation water, surface water, equipment and personnel Tissue damage from nematodes, handling and root damage Infected plant material –In geraniums: spread through the use of infected cuttings

Southern Wilt of Geranium Disease Control No chemical control available Control relies on eradication of infected plants and proper sanitation practices –Limit greenhouse access and practice sterile techniques –Water monitoring for presence of pathogen –Clean irrigation system on a regular basis –Culture index plant material 1-3 years to ensure it is disease free –Practice weed control programs within and around greenhouses Photo © Br. Alfred Brousseau, Saint Mary's College, USDA-APHIS-PPQ Pest Data Sheet Ralstonia solanacearum Race 3 Biovar 2 Lemay et al. 2003

Web Links for Further Information APHIS-PPQ Fact Sheet on Ralstonia solanacerarum Race 3 Biovar 2 ston.pdf Article: Southern Bacterial Wilt caused by Ralstonia solanacearum, Margery Daughtry EPPO Data Sheets on Quarantine Pests: Ralstonia solanacearum Race 3 Biovar 2 Bacterial Wilt, Massachusetts Introduced Pests Outreach Project Pictorial Guide to Geranium Wilt Disorders, NCSU Article: It Pays to Know the Difference, Dr. S.G.P. Nameth, Ohio State University NCIPM Ralstonia solanacearum Race 3 Biovar 2 Pest Alert stalert.pdf

References NPDN Ralstonia solanacearum Race 3 Biovar 2 Training Module no. 020 April 20, 2007