Diseases Management of Cole Crops
1. Leaf Spot and Bight:
Small dark coloured spots which spread rapidly to form circular lesions and concentric rings of dark conidiophores’ appear in humid weather due to which cauliflower develops brown discoloration and cabbage after harvests acquires black mouldy appearances.
i) Hot water treatment of seeds at 50 0 C for 30 minute helps to check the spread of this diseases.
ii) Spraying the crop with Zineb (Dithane Z – 78) or Mancozeb (Dithane M – 45) @ 2.5 gm per liter of water or copper oxychloride (Blitox, Blucopper, Phytolap, cupravit etc.) @ 5 gm per liter of water at an interval of 10- 15 days according to incidence of diseases is very effective to control this disease.
2. Black Rot:
The margin of disease affected leaves turn yellow vein becomes dark and vascular discoloration takes place in the main stem. Cabbage and cauliflower heads are discolored scheduling may die when attacked in young stage.
The disease can be controlled by seed treatment with hot water at 50 0 C or one % mercuric chloride solution for half an hour before sowing and adopting crop rotation with non- cruciferaceuous crops for three years.
3. Club Rot:
The rots of affected plat enlarge to from clubs secondary invasion by soft root bacteria follows forming material toxic to plant. The foliage of affected plants with on sunny days and recovers towards evening.
The seedlings at transplanting time should be treated with mercuric chloride @ 125 c.c (about 113.4 gm).
4. Damping Off:
It is a common problem in the nursery bed of vegetable crops. The affected plants fall down and die due to shrinking of cortical tissue of hypocotyls.
Drenching the nursery bed with formaldehyde or brassicol about 3 -4 weeks prior to sowing, seed treatment with mercurial fungicide @ 2 gm per kg of seed, avoiding thick sowing and spraying the seedlings with Dithane M – 45 or Dithane Z- 78 @ 2.5 gm per liter of water are the common remedial measures.