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United States Department of Agriculture

Agricultural Research Service

Pearl Millet Diseases - Bacterial
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Bacterial spot Pseudomonas syringae van Hall
Bacterial leaf streak Xanthomonas campestris (Pammel) Dowson pv. pennamericanum
Bacterial leaf stripe Pseudomonas avenae Manns
Unnamed bacterial disease Pantoea agglomerans (Ewing & Fife)


 

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, slightly greenish fluorescent in transmitted light. Short, cylindrical rods, 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 glauca), maize.

Geographic distribution:

Iowa, USA

Australia (New South Wales Dept. Agric. 1964)

Nomenclature discrepancies:

Alternative disease name:

Holcus spot

Seed transmission:

Unknown for pearl millet, but has been seed transmitted in napiergrass (Richardson 1979). The pathogen is susceptible to desiccation on glass but resistant on sorghum seed.

Primary citation(s):

(Kendrick 1926)


Bacterial Leaf Streak

Xanthomonas campestris (Pammel) Dowson pv. pennamericanum

Symptoms:

Symptoms are not clearly defined in the literature. Similar to bacterial leaf stripe and streak of sorghum.

Pathogen and disease characteristics:

Yellow, mucoid bacterial colonies in culture. Aerobic, motile, gram-negative, rod-shaped bacteria differing pathologically, serologically, and by membrane protein patterns from other pathovars of X. campestris. Cells measure 0.45 x 2.25 um and have one polar flagellum. Optimal growth occurs between 26 and 30 oC.

Host range:

Pearl millet and proso millet (Panicum miliaceum).

Geographic distribution:

Nigeria. Also collected from Senegal and Niger (L. Claflin, personal communication)

Nomenclature discrepancies:

None.

Seed transmission:

Not known to be seed transmitted.

Primary citation(s):

(Qhobela and Claflin 1988)


 

Bacterial Leaf Stripe

Pseudomonas avenae Manns

Symptoms:

Water-soaking occurring at the ends of advancing interveinal lesions which vary in length from several to more than 25 cm. Older lesions
are usually light brown.

Pathogen and disease characteristics:

Bacteria are positive for acid production from arabinose, fructose, galactose, glucose, glycerol, and sorbitol.
Most utilize citrate and grow at 41 oC.

Host range:

Pearl millet, corn, sorghum, sugarcane in primary citation. Additional hosts cited are barley, wheat, oats, Italian millet, barnyard millet (Panicum crusgalli var. frumentaceum), proso millet, foxtail millet, finger millet, rice, rye, and Vasey grass (Paspalum urvillei).

Geographic distribution:

Nigeria

Nomenclature discrepancies:

None.

Seed transmission:

Not known to be transmitted through seed in pearl millet, but P. avenae has been demonstrated to be seedborne in rice and Vasey grass.

Primary citation(s):

(Claflin et al. 1989)


 

Unnamed Bacterial Disease

Pantoea agglomerans (Ewing & Fife)

Symptoms:

Straw-colored lesions with a chlorotic edge often extending the length of the leaf. Watersoaking at leaf tips and margins occur in seedlings.

Pathogen and disease characteristics:

Bacteria are gram negative, nonfluorescent, fermentative, rod-shaped, and form yellow colonies on nutrient agar.

Host range:

Pearl millet

Geographic distribution:

Zimbabwe, possibly India

Nomenclature discrepancies:

The disease may be the same as bacterial leaf streak or bacterial leaf blotch, reported as being caused by Xanthomonas pennisiti (Rajagopalan and Rangaswami 1958), Xanthomonas annamalaiensis (Rangaswami et al. 1961a) or Xanthomonas rubrisorghi (Rangaswami et al. 1961b) See bacterial leaf streak - bacterial leaf blotch in AQuestionable or Poorly Described Diseases of Pearl Millet Reported in the Literature, page )

Synonym:

Erwinia herbicola

Seed transmission:

Not known to be seed transmitted.

Primary citation(s):

(Frederickson et al. 1997)


Last Modified: 7/21/2010
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