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
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:
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.
Department of Agriculture
The material on this page is in the public
Original posting: June 5, 1999.