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United States Department of Agriculture

Agricultural Research Service

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Pearl Millet Diseases
Bacterial Diseases

Bacterial Spot

Pseudomonas syringae van Hall

Symptoms: Round, oblong, linear, or irregular water-soaked leaf spots expand to form oval to elongate, tan necrotic lesions with a thin, dark-brown margin (Jensen et al. 1991).

Pathogen and disease characteristics: Colonies in culture are grayish white in reflected light and slightly greenish fluorescent in transmitted light. The short, cylindrical rods have 1 to 4 polar flagella at one pole. No spores, aerobic, gram negative. Temperature for growth ranges from 0 to 35 ºC, with optimum temperatures between 25 and 30 ºC. Resistant to freezing in water.

Host range: Pearl millet, napiergrass, sorghum, sudangrass, johnsongrass, foxtail (Chaetochloa lutescens old nomenclature, now Setaria glaucum), maize.

Geographic distribution: USA (Iowa); Australia (New South Wales 1964).

Nomenclature discrepancies: Alternative disease name: Holcus spot.

Seed transmission: Unknown for pearl millet, but this pathogen has been transmitted by seed in napiergrass (Richardson 1979). It is susceptible to desiccation on glass but is resistant on sorghum seed.

Primary citation: Kendrick 1926.


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United States Department of Agriculture
Agricultural Research Service

The material on this page is in the public domain.

Original posting: June 5, 1999. 

Last Modified: 2/6/2002
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