AVRDC International Cooperators'
Fact Sheet

Tomato Diseases


Bacterial Wilt
Ralstonia solanacearum,
formerly Pseudomonas solanacearum

Most severe in tropical and subtropical climates with high rainfall

infected plant in greenhouse


Damage Symptoms

This disease occurs in scattered plants or groups of plants. The initial symptom is wilting of terminal leaves, followed in 2-3 days by a sudden and permanent wilt. Adventitious roots may develop on the main stems.

Additional symptoms include vascular browning, water soaking of pith followed by browning, and in later stages browning of cortex near the soil line. Bacteria streaming can be seen when a freshly cut stem is suspended in water.


Conditions for Development

Tomato is the most susceptible crop, but Bacterial Wilt also infects tobacco, potato, eggplant, pepper, banana and over 200 other species.

The pathogen survives in soil for extended periods without a host plant. It enters roots through wounds, which may be caused by insects, nematodes, and cultivation. High temperature and high soil moisture favor disease development.

 

infected plant in field

Suddenly wilted plant with no yellowing
 

bacteria streaming

Bacteria streaming from freshly cut stem
     

Control

No effective chemical control. Use disease-free transplants. When producing transplants, pasteurize the soil or fumigate the plant beds. Rotation with non-susceptible crops has limited value, although rotation with flooded rice reduces the incidence of disease. Tolerant cultivars may allow for 70-80% survival. Use raised beds for good drainage. Keep soil pH at 5.5 or higher. Avoid nematode-infested fields.
 


Last updated: 2001. 
Information from:
Vegetable Diseases: A Practical Guide. Lowell L. Black, AVRDC; and AVRDC International Cooperators's Guide on Suggested Cultural Practices for Tomato.
 

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