Bacterial stem canker

Bacterial stem canker is a plant disease incited by the bacterium Pseudomonas andropogonis. This pathogen is known for infecting the vascular tissues of various plants, disrupting their internal transport systems and causing severe physiological stress to the host crops.

The disease primarily affects crops such as chickpeas, sorghum, maize, and several other leguminous and grassy plants. It acts as a systemic infection that can invade the plant through natural openings like stomata or through various types of wounds, including those inflicted by pests or agricultural machinery during field operations.

Symptoms typically manifest as small, water-soaked spots on stems, petioles, and leaves, which eventually turn necrotic and dark brown or black. As the infection progresses, these spots develop into elongated cankers or sunken lesions. Under high humidity, a bacterial ooze may be visible on the surface of the lesions, which is a diagnostic sign of the disease.

Environmental conditions play a crucial role in the development and spread of Pseudomonas andropogonis. Warm, humid weather with frequent rain or irrigation promotes the proliferation of the bacteria. The pathogen survives in infested crop debris, soil, and contaminated seeds, making it a persistent threat in agricultural environments where crop rotation is not strictly followed.

The economic impact is significant due to reduced yield and poor seed quality in affected crops like chickpeas. To effectively manage this disease, farmers should implement integrated pest management strategies.

• Use certified, disease-free seed lots.
• Rotate crops with non-host species to break the disease cycle.
• Ensure thorough soil cultivation to bury and decompose infected plant materials.
• Control insect populations that might create entry wounds for the bacteria.