Basal glume rot
Pseudomonas syringae pv. atrofaciens (McCulloch 1920) Young et al. 1978
Bacterial leaf blight
Pseudomonas syringae subsp. syringae van Hall 1902
- Symptoms: The leaves, culms, and spikes of wheat and triticale can be infected. Infections begin as small, dark green, water-soaked lesions that turn dark brown to blackish in color. On the spikelets, lesions generally start at the base of the glume and may eventually extend over the entire glume (picture at left). Diseased glumes have a translucent appearance when held toward the light. Dark brown to black discoloration occurs with age. The disease may spread to the rachis, and lesions may also develop on the kernels (picture at right).Under wet or humid conditions, a whitish gray bacterial ooze may be present. Stem infections result in dark discoloration of the stem; leaf infections result in small, irregular, water-soaked lesions. Symptoms can be confused with those of other bacterial diseases, genetic melanism (false black chaff), septoria blotch, and frost damage.
- Development: The pathogen survives on crop debris, as well as various grass hosts. It is disseminated by splashing rain or by insects, and can be seed borne.
- Hosts/Distribution: The disease can affect all small grain cereal crops; distribution is worldwide.
- Importance: Basal glume rot usually is not economically important, but is frequently reported in humid cereal-growing areas.