Massachusetts
Introduced Pests Outreach Project

Bacterial Wilt

(Click on an image below to see the captioned full-size version)
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Scientific Name: Ralstonia solanacearum race 3 biovar 2
(formerly Pseudomonas solanacearum)

Common Names: bacterial wilt, Southern bacterial wilt, Southern wilt, brown rot

Known Hosts:
Geranium (Pelargonium spp.)
Solanaceous crop plants including potato (Solanum tuberosum), eggplant (Solanum melongena), and tomato (Lycopersicon esculentum).
Solanaceous weeds may act as host reservoirs including climbing nightshade (Solanum dulcamara) and stinging nettle (Urtica dioica).

Symptoms
Geranium
Wilting begins with lower leaves and petioles and works its way up the plant. (Figure 1)
Wilted leaves with chlorotic, wedge-shaped areas or chlorotic and/or necrotic leaf margins. No leaf spots are evident. (Figure 2)
Eventually entire plant collapses on the medium (Figure 3)
White runny ooze from cut stems (Figure 4)
 
Potato
Wilting of the leaves at the end of the day with recovery at night. Plant will eventually fail to recover and die. (Figure 5)
Brown staining of vascular ring. Pus may exude from the ring when the tuber is squeezed. (Figures 6 and 7)
Pale ooze may exude from eyes and heel end of potato. Soil will adhere to the oozing eyes. (Figure 8)
Cross-section of a stem placed in water will exude milky white strands

Similar disease or symptoms:
Geranium
Bacterial blight caused by Xanthomonas campestris pv. pelargonii causes leaf spots in addition to wilting.
This article on Ohio Floriculture Online discusses the differences in the two diseases. http://floriculture.osu.edu/archive/apr02/Bacterial.html

Wilting can have a variety of causes including root rot, high fertilizer salts or water stress.

Potato
Wilting of potato leaves can also be due to water stress.

Brown staining of vascular ring is also a symptom of ring rot caused by Clavibacter michiganensis subsp. sepedonicus. See Department for Environment, Food, & Rural Affairs, UK webpage for a comparison. http://www.defra.gov.uk/planth/pestnote/ringrot.pdf

Fact sheets and references:
USDA/APHIS/PPQ Ralstonia web page
http://www.aphis.usda.gov/plant_health/plant_pest_info/ralstonia/index.shtml

UMass Extension Floriculture Team
http://www.umass.edu/umext/floriculture/fact_sheets/pest_management/south_bact_wlt.html

USDA National Agriculture Library Species Profile for Southern Bacterial Wilt
http://www.invasivespeciesinfo.gov/microbes/bacterialwilt.shtml

NAPPO Phytosanitary Alert System
http://www.pestalert.org/Detail.CFM?recordID=70

EPPO Data Sheet on Quarantine Pests: Ralstonia solanacearum
http://www.eppo.org/QUARANTINE/bacteria/Ralstonia_solanacearum/PSDMSO_ds.pdf

Canadian Food Inspection Agency
http://www.inspection.gc.ca/english/sci/surv/data/ralsole.shtml

Bacterial wilt of potatoes,Department of Agriculture, Western Australia, Farmnote 84/88
http://www.agric.wa.gov.au/content/PW/PH/DIS/VEG/FN084_1988.HTM

International Potato Center (CIP), Peru: Information on bacterial wilt symptoms, research, and control
http://www.cipotato.org/potato/pests_diseases/bacterial_wilt/symptoms.asp

last reviewed February 25, 2008


Massachusetts Department of Agricultural Resources
Massachusetts Introduced Pests Outreach Project is a collaboration between the Massachusetts Dept. of Agricultural Resources and the UMass Extension Agriculture and Landscape Program. This website was made possible, in part, by a Cooperative Agreement from the United States Department of Agriculture's Animal and Plant Health Inspection Service (APHIS). It may not necessarily express APHIS' views.