Bacterial Blight, a New Disease of Broccoli Caused by Pseudomonas syringae in California

2000 ◽  
Vol 1 (1) ◽  
pp. 35 ◽  
Author(s):  
S. T. Koike ◽  
N. A. Cintas ◽  
C. T. Bull
Keyword(s):  
Brassica Oleracea ◽  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
New Disease ◽  
Salinas Valley ◽  
Monterey County

In 1998 and 1999, a new disease was detected in commercial broccoli (Brassica oleracea var. botrytis) grown in the Salinas Valley, Monterey County, CA. Posted 1 June 2000.

scholarly journals Bacterial Blight of Broccoli Raab: A New Disease Caused by a Pathovar of Pseudomonas syringae

Plant Disease ◽  
1998 ◽  
Vol 82 (7) ◽  
pp. 727-731 ◽  
Author(s):  
Steven T. Koike ◽  
Diana M. Henderson ◽  
Hamid R. Azad ◽  
Donald A. Cooksey ◽  
E. L. Little
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
Toxin Production ◽  
Grass Species ◽  
New Disease ◽  
Leaf Spots ◽  
Leaf Yellowing ◽  
Salinas Valley ◽  
Cruciferous Plants ◽  
Test Plants

Bacterial blight is a new disease of broccoli raab or rappini (Brassica rapa subsp. rapa) that has developed on commercially grown crops in the Salinas Valley (Monterey County) in California. Symptoms consist of small, angular, water-soaked flecks on lower foliage that are visible from both adaxial and abaxial sides of the leaves. These flecks expand and become surrounded by bright yellow borders. With time, multiple leaf spots coalesce and result in large, irregular necrotic areas, extensive leaf yellowing, and eventual leaf death. If symptoms develop on the uppermost leaves attached to the inflorescence, the shoot loses market quality and will not be harvested. Pseudomonas syringae was consistently isolated from symptomatic plants, and selected strains caused similar symptoms when inoculated onto broccoli raab test plants. Broccoli raab strains caused leaf spot symptoms on nine other Cruciferous plants, as well as on three grass species (California brome, oat, and common timothy). Conversely, broccoli raab was not infected by P. syringae pathovars coronafaciens, maculicola, and tomato. Broccoli raab strains were positive for coronatine toxin production. Fatty acid analyses indicated that the P. syringae from broccoli raab was most closely related to P. syringae pvs. coronafaciens and maculicola, but its distinct host range suggests that it may be considered a separate pathovar.

scholarly journals Bacterial Blight, a New Disease of Broccoli Caused by Pseudomonas syringae in California

Plant Disease ◽  
2000 ◽  
Vol 84 (3) ◽  
pp. 370-370 ◽  
Author(s):  
S. T. Koike ◽  
N. A. Cintas ◽  
C. T. Bull
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
Acid Methyl Ester ◽  
Hypersensitive Reaction ◽  
Nutrient Broth ◽  
New Disease ◽  
Initial Symptoms ◽  
Salinas Valley ◽  
Bacterial Blight Pathogen ◽  
Dark Green

In 1998 and 1999, a new disease was detected in commercial broccoli (Brassica oleracea var. botrytis) grown in the Salinas Valley, Monterey County, CA. Initial symptoms consisted of large, water-soaked, dark green, angular leaf sections that were bordered by major leaf veins. Diseased areas were as large as 10 × 3 cm. As the disease developed, affected areas turned tan and papery, and leaf margins sometimes became tattered. The numerous small (<1 cm diameter), round to angular spots that also were present retained their size and did not develop into larger lesions. A blue-green fluorescing pseudomonad was consistently isolated from both types of lesions on King's medium B. Strains were levan positive, oxidase negative, and arginine dihydrolase negative. Strains did not rot potato slices but induced a hypersensitive reaction in tobacco (Nicotiana tabacum L. ‘Turk’). Fatty acid methyl ester analysis (MIS-TSBA version 4.10, MIDI, Inc., Newark, DE) indicated that the strains were highly similar (similarity ≥0.843) to Pseudomonas syringae. Biolog GN (version 3.50, Biolog, Inc., Hayward, CA) profiles also identified the strains as P. syringae. Therefore, the bacterium associated with the disease was identified as P. syringae. Pathogenicity of 13 strains was demonstrated by greenhouse tests. The strains were grown as nutrient broth shake cultures for 48 h at 24°C, diluted to 106 CFU/ml, and misted onto broccoli (cvs. Patriot and Titleist) and broccoli raab (B. rapa subsp. rapa cv. Spring). Control plants were misted with sterile nutrient broth. After 4 to 5 days in a greenhouse (24 to 26°C), large angular leaf lesions developed on all inoculated broccoli and broccoli raab plants. Strains were reisolated from symptomatic tissue and identified as P. syringae. Control plants remained symptomless. The results of two sets of pathogenicity tests were the same. Unlike most P. syringae strains, those isolated from broccoli were sensitive to a bacteriophage recovered from a P. syringae pathovar that infects broccoli raab. These results suggest that the broccoli pathogen may be related to the bacterial blight pathogen of broccoli raab (1). This is the first report of this pathogen causing a disease on commercially grown broccoli. Reference: (1) S. T. Koike et al. Plant Dis. 82:727, 1998.

scholarly journals Bacterial Blight of Shallot, Caused by Pseudomonas syringae pv. porri, a New Disease in Korea

2012 ◽  
Vol 28 (4) ◽  
pp. 454-454 ◽  
Author(s):  
Inn-Shik Myung ◽  
Young-Kee Lee ◽  
Hongsik Shim
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
New Disease

scholarly journals Bacterial Leaf Spot of Celery in California: Etiology, Epidemiology, and Role of Contaminated Seed

Plant Disease ◽  
1997 ◽  
Vol 81 (8) ◽  
pp. 892-896 ◽  
Author(s):  
E. L. Little ◽  
S. T. Koike ◽  
R. L. Gilbertson
Keyword(s):  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Field Tests ◽  
Hot Water ◽  
Disease Development ◽  
Bacterial Leaf Spot ◽  
Overhead Irrigation ◽  
Celery Seed ◽  
Salinas Valley

Pseudomonas syringae pv. apii, causal agent of bacterial leaf spot (BLS) of celery, was first identified in California in 1989. By 1991, BLS was apparent in all celery-growing areas of the state. Greenhouse-produced transplants were affected most severely, and disease incidence approached 100% in some greenhouses. In this study, sources of inoculum and factors contributing to disease development were investigated in three Salinas Valley greenhouse operations during the 1991, 1992, and 1993 celery transplant seasons (January to August). Epiphytic P. syringae pv. apii was not detected on celery transplants until April or May of each year. Increased epiphytic populations preceded BLS outbreaks, and high-pressure, overhead irrigation favored bacterial infiltration and disease development. In seed-wash assays, P. syringae pv. apii was recovered from 5 of 24 commercial celery seed lots. In field tests, epiphytic P. syringae pv. apii was found on umbels of inoculated celery plants, and seeds from these plants were heavily contaminated with P. syringae pv. apii. Contaminated seed produced seedlings with large epiphytic P. syringae pv. apii populations. Hot-water treatment (50°C for 25 min) eliminated >99.9% of seed contamination. Based on these results, disease management techniques are proposed.

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