Introduced Pests Outreach Project

Bacterial Wilt

(Click on an image below to see the captioned full-size version)
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Figure 8

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).

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)
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:
Bacterial blight caused by Xanthomonas campestris pv. pelargonii causes leaf spots in addition to wilting.
Visit the following link for an article by Dr. Sharon M. Douglas, of The Connecticut Agricultural Experiment Station, which discusses the differences in the two diseases and includes a comparison chart:

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

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.
Please visit the following links for a comparison:
--- Department for Environment, Food, & Rural Affairs, UK:.
--- Department of Agriculture and Rural Development, Northern Ireland UK:

Fact sheets and references:
USDA/APHIS/PPQ Ralstonia web page

EPPO Data Sheet on Quarantine Pests: Ralstonia solanacearum

International Potato Center (CIP), Peru: Information on bacterial wilt symptoms, research, and control

UMass Extension Floriculture Team

USDA National Agriculture Library Species Profile for Southern Bacterial Wilt

NAPPO Phytosanitary Alert System

Canadian Food Inspection Agency

Department of Agriculture, Western Australia: Ralstonia solanacearum Fact Sheet

last reviewed December 23, 2014


Massachusetts Department of Agricultural Resources
The Massachusetts Introduced Pests Outreach Project is maintained by staff at the Massachusetts Dept. of Agricultural Resources. 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 (USDA APHIS). It may not necessarily express APHIS' views.