Club root(Plasmodiophora brassicae)

Symptoms

• Cool, wet and acidic soils favor the development and spread of the disease.
• Roots develop clubs (swellings) that can be 12-15 cm wide.
• The largest clubs are usually on the larger roots just below the soil surface.
• Infection in the nursery stage results in the death of seedlings.
• When plants are attacked at a later stage, the disease rarely kills the plant, but the capacity of the affected roots to absorb minerals and water gets reduced.
• Plants wilt in hot weather but partly recover at night.
• Finally leaves become stunted, yellowish and prematurely bolt in hot weather.

Management

• Use certified seeds
• Long crop rotations with non-cruciferous crops for 6 years or longer help prevent a pathogen build- up and reduce disease incidence.
• When susceptible varieties are grown in acidic soils, finely ground limestone is thoroughly mixed into the soil six weeks before planting to raise the soil pH above 7.0.

Chemical Control

Extremely Toxic

Highly Toxic

Moderately Toxic

Slightly Toxic