This document summarizes several bacterial diseases that affect tomatoes, including bacterial wilt caused by Pseudomonas solanacearum. It describes the symptoms of bacterial wilt as flaccid leaves, wilting, adventitious roots on stems, and yellow or brown discoloration of the stem. The pathogen survives in soil and enters through wounds, multiplying in the vascular system and blocking water transport. It can be disseminated by water, soil movement, or infected transplants. Management includes crop rotation, soil fumigation, growing seedlings in disease-free nurseries, and using resistant cultivars.

1. Bacterial Diseases of Tomato
As In Compendium of Tomato Diseases
By American Phytopathological Society, 1993
Presented By
Madhu Sudhan Ghimire
PLP-02M-2015
Department of Plant Pathology
Agriculture and Forestry University

2. • Bacterial Canker (Clavibacter michiganensis subsp.
Miciganensis)
• Bacterial Speck( Pseudomonas syringae pv. Tomato)
• Bacterial Spot (Xanthomonas campestris pv vesicatoria)
• Bacterial Stem Rot (Erwinia carotovora subsp.
Carotovora)
• Bacterial Wilt (Pseudomonas solanacearum)
• Syringae Leaf Spot (Pseudomonas syringae pv.
syringae)
• Tomato Pith Necrosis (Pseudomonas corrugata)
• Bacterial Soft Rot (group of bacterium)

3. Bacterial Wilt of Tomato
(Pseudomonas solanacearum)
• Bacterial wilt is a serious disease of tomato in
many warm, temperate, subtropical and tropical
regions of the world.
• The incidence of disease may range from a few
scattered plants or loci of infection in fields.

4. Symptoms
• Appears as flaccidity in one or more of the youngest leaves.
• Under favorable conditions a rapid and complete wilt soon
follows.
• Adventitious roots may appear in the stem of the infected
plants.
• The LS/TS of plant appears yellow or light brown in early
stages which turns dark brown later.
• Massive invasion of the cortex may result in the appearance
of water soaked lesions on the external surface.
• Dirty white or yellow viscous ooze exude off the severe
vascular bundles when cut and immersed in clean water.

5. Disease Cycle and Epidemiology
• P. solanacearum attacks more than 200 species of cultivated
plants and weeds in 33 plant families.
• The organism survives in the soil for the extended period in
absence of host plants, well drained soils with good water
retention characters are conductive.
• Moderate to high temperature (30-35˚C) and low to
moderate PH favors the pathogen.
• Bacterium enters roots through wounds and has affinity to
the vascular system where it multiplies rapidly filling the
xylem system with the cells and the slime.
• Wilt occurs in 2-5 days of the infection.
• Bacterium is released by the exudates or decomposition of
infect. Bacterium is disseminated by running water, soil
movement or movement of infected transplants.

6. Control/Management
• Difficult to control. Crop rotation with non susceptible crop
provides some control.
• Soil treatment with a general purpose fumigant reduces
disease incidence but is expensive and does not offer season-
long control.
• Production of seedlings in the disease free nursery drenched
with soil fumigants.
• Bacterial wilt resistant cultivars must be used. (Venus, Saturn)

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