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United States Department of Agriculture

Agricultural Research Service

Pearl Millet Diseases:Fungal: Phyllachora Leaf Spot

Pearl Millet Diseases
Fungal Diseases

Phyllachora Leaf Spot

Phyllachora penniseti Syd.

Symptoms: Leaves can be covered with numerous small, elongate, dark or black pustules that are 2-3 mm long when isolated but become confluent in mass. Both surfaces of the leaves can be affected. Symptoms usually develop after most vegetative growth has occurred or during grain fill.

Pathogen and disease characteristics: Pseudopycnidia develop in the stroma under the epidermis. Elliptical, cylindrical, unicellular, hyaline conidia measure 10-15 × 2.5-3 µm in diameter.

Host range: Pearl millet, napiergrass (Moreau 1949). Also described on Pennisetum benthami Stend. (Saccas 1954).

Geographic distribution: Chad, Niger, Tanzania (Wallace and Wallace 1949). Republic of Guinea (and possibly Uganda, see below) on napiergrass (Moreau 1949).

Nomenclature discrepancies: Synonyms or similar pathogens: Described as anamorphic Placosphaeria sp. in Saccas (1954) and Jouan and Delassus (1971). Leptosphaeria penniseti was isolated from napiergrass in Uganda was associated with Phyllachora and Stagonospora (Moreau 1949). Saccas (1954) indicates asci and ascospore dimensions of L. penniseti were consistent with Phyllachora penniseti, although dimensions of L. penniseti differ from P. penniseti in Moreau (1949).

Alternative disease name: Tar spot.

Seed transmission: Not demonstrated to be transmitted by seed.

Primary citations: Saccas 1954, Jouan and Delassus 1971.


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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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