Causal Organism:  plasmodiophora brassicae

Symptoms

• Swelling or malformation on the main lateral roots those are called club roots and those galls appear like clubs or spindles on the roots.
• The crop can be completely destroyed due to damage

Management

• Keeping the soil at a slightly basic pH of 7.1 – 7.2 by the addition of agricultural lime and apply 2-4 t/ha of lime to raise soil pH.
• Use of disease free planting materials
• As well as the integration of crop rotation

Causal Organism : Erysiphe cruciferarum

Symptoms

• Small white patched on upper and lower surface which may also show purple blotching , later powdery layer can be seen which coats the leaves
• leaves become chlorotic and drop from plant

Management

• Plant resistant varieties
• rotate crops
• Remove all crop debris after harvest
• Remove weeds
• Application of surface sprays, dusts or vapors

Causal Organism: Peranospora parasitica

Symptoms

• Infections of downy mildew begin as irregular yellow patches on leaves
• These chlorotic lesions later turn brown
• If conditions are favorable white fluffy growth of the fungus develops on the undersides of leaves

Management

• Covering the nursery to protect it from rain
• In the morning , remove the cover and allow get the sunlight
• Apply of a fungicide containing tebuconazole (5 ml for 10 liters of water) for once is recommended.