Info

• Submitted by Mary McKellar, NEPDN

• Prepared January 2008

Southern Wilt of Geranium Southern Wilt of Geranium Why is this a problem?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

Race Host Range Geographic Distribution

Biovar

1 Wide Asia, Australia, Americas

3,4

1

2 Banana

Other Musa spp.

Caribbean,Brazil

Philippines

1

3 Potato, some

other

Solanaceae,

Geranium;

Worldwide except US and Canada

2

4 Ginger Asia 3,4

5 Mulberry China 5

Southern Wilt of GeraniumSouthern Wilt of GeraniumPathway into the U.S.Pathway into the U.S.

Introduction into the U.S. hasbeen through the importation ofgeranium cuttings obtainedfrom production greenhouseslocated 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 Cases2001

No Reported Cases2002

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 - Yet2005 - 2006

Photo Peggy Greb, USDA-ARS

Southern Wilt of GeraniumSouthern Wilt of Geranium

What does it look like?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, www.pdis.org

• 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, www.pdis.org

Photo David B. Langston, University of Georgia, www.forestryimages.org

Bacterial Streaming

Southern Wilt of GeraniumSouthern Wilt of GeraniumWhat does it look like?What does it look like?

Southern Wilt of Geranium Southern Wilt of Geranium Disease TransmissionDisease 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 Southern Wilt of Geranium Disease Control 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,

http://calphotos.berkeley.edu/

USDA-APHIS-PPQ Pest Data Sheet Ralstonia solanacearum Race 3 Biovar 2 Lemay et al. 2003

Web Links for Further InformationWeb Links for Further InformationAPHIS-PPQ Fact Sheet on Ralstonia solanacerarum Race 3 Biovar 2

http://www.aphis.usda.gov/publications/plant_health/content/printable_version/faq_phra

ston.pdf

Article: Southern Bacterial Wilt caused by Ralstonia solanacearum, Margery Daughtry

http://www.greenhouse.cornell.edu/pestsdis/MD.SAFtalk.pdf

EPPO Data Sheets on Quarantine Pests: Ralstonia solanacearum Race 3 Biovar 2

http://www.eppo.org/QUARANTINE/bacteria/Ralstonia_solanacearum/PSDMSO_ds.pdf

Bacterial Wilt, Massachusetts Introduced Pests Outreach Project

http://massnrc.org/pests/pestFAQsheets/ralstonia.html

Pictorial Guide to Geranium Wilt Disorders, NCSU

http://www.ces.ncsu.edu/depts/hort/floriculture/GeraniumWilt.pdf

Article: It Pays to Know the Difference, Dr. S.G.P. Nameth, Ohio State University

http://floriculture.osu.edu/archive/apr02/Bacterial.html

NCIPM Ralstonia solanacearum Race 3 Biovar 2 Pest Alert

http://www.aphis.usda.gov/plant_health/plant_pest_info/ralstonia/downloads/ralstoniap

stalert.pdf

ReferencesReferences• NPDN Ralstonia solanacearum Race 3

Biovar 2 Training Module no. 020 April 20, 2007