Bacterial Diseases of Tomato As In Compendium of Tomato Diseases

By American Phytopathological Society, 1993

Presented ByMadhu Sudhan Ghimire

PLP-02M-2015Department of Plant Pathology

Agriculture and Forestry University

• 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)

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.

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.

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.

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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