Damping off
Damping off:
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C.O: Pythium aphanidermatum (Eds.) Fitz
(Class: Oomycetes; Order: Peranosporales; Family: Pythiaceae)

Symptoms:

• Infection usually starts on the germinating seeds.
• Spread to the hypocotyls, basal stems and developing tap root.
• Affected seedlings are pale green.
• Brownish water soaked lesions at the basal portion of the stem.
• Lesion girdles the stem, extending up and downwards.
• Affected tissues rot and the seedling collapse.

Management:

• Use ratified seeds for sawing.
• Treat the seed with metalaxyl @ 3 g/Kg seed.
• Privide better drainage by forming raised bed.
• Recommended seed rate to be applied.
• Drench the copper oxychloride fungicides @ 0.25% on the on set of disease


Black rot

Black rot
Black rot:
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C. O.: Xanthomonas campestris (Pammel) Dowson
(Sub division: Bacteria; Order: Pseudomonadales; Family: Pseudomonadaceae)

Symptoms:

• Chlorotic lesions starts near the leaf margin
• Progress towards the centre in the form of V-shaped yellowish spots
• Affected veins and veinlets turn brown and finally black is the distince characteristics of disease
• Root system may infected in advance stages vascular blackening and bacterial ooze may seen
• Plants affected in young stage may wilt and die.

Management:

Use of black rot tolerant varieties
seeds are treated with Agrimycin-100 (100ppm) or Streptocycline (100 ppm).
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 and the affected plants should be removed and destroyed.


Club root
Club root:
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C. O.: Plasmodiopara brassicae Woronion
(Class: Plasmodiophoromycetes; Order: Plasmodiophorales; Family: Plasmodiophoraceae)

Symptoms:

• Affected plant root are malformed into club like structures distinct characteristics of disease
• Malformed tissues rot and turn black
• Above ground plant parts show stunting, reduction in the size of head or chlorosis

Management:

• Use disease resistant varieties
• Serve in acidic soils, hence apply lime @ _____ ton/ha to increase soil pH


Blight
Blight:
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C.O.: Alternaria brassicae (Berk.) Sacc.

Symptoms:

Older leaves are more susceptible.
The initial symptoms are in the form of small dark yellow spots on the leaf surface. Later on the spots enlarge to circular areas with concentric rings and possibly surrounded by yellow halos.
In severe cases, the entire plant defoliates.
Violets to tan spots develop on infected cabbage seed pods which intensifies in wet weather.