Black rot(Xanthomonas campestris pv. campestris)

Symptoms

• Affect all stages of crop. On young seedlings, the cotyledons show blackening at the margins.
• Infected seedlings become yellow, drop lower leaves and may die.
• Leaves may be affected on only one side of a seedling.
• In main field, the classic symptom of black rot is caused by local infection that results when bacteria enter leaves through natural openings of leaf margins.
• The infected tissue turns pale green-yellow and then turns brown and dies.
• Affected areas are usually wedge- or V-shaped.
• These areas enlarge as the disease progresses, and severely affected leaves may drop off.
• The veins in infected leaves, stems, and roots sometimes become black.
• The heads of the infected plants remains small and its quality is reduced making it unfit for marketing.

Management

• Use of black rot tolerant varieties is the best method to control the disease.
• Planting should be done on raised beds to facilitate drainage.
• Cultivation in the fields where crucifers have been continuously grown during last 2 years should be avoided.
• Plants should be thoroughly inspected for black rot symptoms.
• Affected plants should be removed and destroyed
• Treat seeds with Pseudomonas fluorescens (20 g/litre of water/ kg of seed) and soil application of Pseudomonas fluorescens fortified in neem cake also reduces the disease incidence.

Chemical Control

Extremely Toxic

Highly Toxic

Moderately Toxic

Slightly Toxic