Taxonomy

Domain	Bacteria
Phylum	Proteobacteria
Class	Gammaproteobacteria
Order	Pseudomonadales
Family	Pseudomonadaceae
Genus	Pseudomonas

Scientific Name

Pseudomonas corrugata

Common Name

bacterial pith necrosis

Author: John Bonkowski, Bacheline Joseph, Deanna Bayo, University of Florida

Reviewed by:Name, Organization

Pathogen

Pseudomonas corrugata is a gram-negative, aerobic bacterium with multitrichous polar flagella (6). This pathogen is primarily associated with causing pith necrosis and leaf tip chlorosis in tomatoes (4). Multiple Pseudomonas spp. have been found to cause tomato pith necrosis, including: P. cichorii, P. mediterranea, P. viridiflava, P. fluorescens, and other unidentified Pseudomonas spp. (3). This bacterium has also been isolated from alfalfa roots exhibiting no symptoms (3, 5).

Symptoms and Signs

Chlorosis of young leaves and upper portion of the stem are initial symptoms of tomato pith necrosis. Chlorosis and wilting develops in the top portion of the plant along with necrosis of the lower stem when infection is severe. Infected stems may not show external lesions, but the tomato plant’s pith will gradually turn brown and necrotic. The stem may become chambered or hollow following pith necrosis. This hollowing can lead to the cracking and breaking of the plant stems. Tomato plants may also produce excessive amounts of adventitious roots in response to the death of the main stem. Often, the initial symptoms will look destructive, but the disease may not progress. Death is not always certain in infected plants (2,7).

Ecology and Spread

Pseudomonas corrugata is favored by low night temperatures, high humidity, and high nitrogen. This pathogen is capable of growing in temperatures up to 37°C (2). Natural openings and wounds on the roots, stem, and base of the plant provide an entryway for the pathogen. Contaminated equipment and irrigation water can spread bacteria from plant to plant. Free water on stems and leaves promote infection, which develops when the first fruit set reach mature green stage (3). This bacterium may be transmitted to seed during fruit development (1,7).

Geographic Distribution

Europe

Belarus, Denmark, France, Germany, Greece, Italy (Sardinia and Sicily), Latvia, Poland, Portugal, Russia (Moscow and Saratov), Spain, Sweden, Switzerland, United Kingdom (England).

Asia

India, Israel, Japan, Russia, Siberia, Syria, Turkey.

Africa

Canary Isles, South Africa.

North America

Canada (Ontario, Quebec), United States of America (California, Florida, Louisiana, Massachusetts, North Carolina).

South America

Argentina, Brazil.

Oceania

New Zealand.

Management

Management of any pathogen is often dependent upon both cultural and chemical options. Consult your local extension specialist or agent for recommendations relevant to your particular host and state. Remember: the label is the law.

Diagnostic Procedures

Procedures/Media	Result for Pseudomonas corrugata
KOH test	Positive; stringing is observed (Gram-negative)
Oxidase	Positive; blue color change
Kings medium B	Negative; nonfluorescent
Nutrient agar	White to cream-colored colonies
Yeast extract-dextrose CaCO3 medium	White to cream-colored colonies
Sucrose peptone agar	Negative; colonies are not mucoid
Hypersensitive Response	Tomato: Positive; necrotic area
	Tobacco: Negative; no reaction
Miller-Schroth medium	Blue-green colored colonies after 24 hours
Crystal violet pectate medium	Negative; no pitting observed
Arginine Dihydrolase	Negative; no color change
Aerobe-anaerobe test	Aerobic; cloudy at the top of the medium

Selected References

1. Fatmi, M., Collmer, A., Iacobellis, N. S., Mansfield, J. W., Murillo, J., Schadd, N., Ullrich, M. 2008. Pseudomonas syringae Pathovars and Related Pathogens: Identification, Epidemiology, and Genomics. Springer Science and Business Media, B. V.

2. Jones, J. B. 1991. Compendium of Tomato Diseases. American Phytopathological Society, St. Paul, MN. 27.

3. Jones, J. B., Zitter, T. A., Momol, T. M., Miller, S. A. 2014. Compendium of Tomato Diseases and Pests. 2nd ed. American Phytopathological Society, St. Paul, MN. 27.

4. Kado, C. I. 2010. Plant Bacteriology. American Phytopathological Society, St. Paul, Minnesota. 72.

5. Lukezic, F. L. 1979. Pseudomonas corrugate, a pathogen of tomato, isolated from symptomless alfalfa roots. Phytopathology 69: 27-31.

6. Scarlett, C.M., Fletcher, J.T., Roberts, P. and Lelliott, R.A. 1978. Tomato pith necrosis caused by Pseudomonas corrugata n. sp. Ann. Appl. Biol. 88; 105–114.

7. University of California. 2009. Pest Management Guidelines: Tomato. Online: http://www.ipm.ucdavis.edu/PDF/PMG/pmgtomato.pdf

Resources and References

Acknowledgements

National Institute of Food and Agriculture, U.S. Department of Agriculture, under Agreement No. 2011-41530-30708 as part of "Diagnostic Image Series Development for Supporting IPM in the Southern Region" (USDA-NIFA-RIPM-003351)