Black Rot

HOSTS

• Brassicas

DESCRIPTION

Black rot is often introduced to fields through infected seeds, but can also be spread by infected plant debris, contaminated water, and tools. The bacteria can survive for up to two years on contaminated plant debris. 

BIOLOGY

The bacterium invades the host plant through pores on the foliage and wounds. Once inside the plant, the bacterium will move into the stem and roots of the host, becoming systemic. Xanthamonas campestris pv campestris produces a viscous sugar that blocks the host's xylem, which moves water throughout the plant. Secondary infections of soft rots are common once a plant is infected with black rot.

SYMPTOMS

• V-shaped lesions on leaf margins 
• Wilted or necrotic foliage 
• Darkened veins on plant roots

GENERAL MANAGEMENT

• Use certified disease-free seeds 
• Avoid watering practices, such as overhead irrigation, that result in wet soil and plants for prolonged periods 
• Ensure proper ventilation by spacing plants apart
• Rotate brassicas with non-susceptible crops 
• Remove infected plants and crop residue from gardens 
• Sanitize tools and equipment