Alternaria blight
1.Alternaria blight:
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Alternaria brassicae

Symptoms:

 Irregular lesions surrounded by chlorotic haloes are produced on the leaves and petioles.
 The spots get enlarged to cover the entire leaf blade with girdling the petiole to cause blighting of the leaves.
 Entire foliage get blighted.
 Seeds get shriveled and content low oil.
 Grain yield is reduced.

Management:

 Spray chlorothalonil @ 0.25 % or mancozeb 0.2%.
 Spray brestan0.05% after initiation of disease and repeat after 15-20 days.
 Remove the infected plant debris and destroy it .


Downy mildew
2.Downy mildew:
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Peronospora brassicae

Symptoms:

 It is common among young plants, but also appears on mature plants.
 The disease is characterized bu the appearance of purplich-brown spots on the underside of the leaves.
 The spots may remain small or become enlarged.
 The upper surface of the leaf on the lesion is yellow.
 Sometimes white rust is also found side by side on the same leaf and the symptoms of the two look very much similar from a distance.
 The stem also get infected and swell up with malformed siliques.

Management:

 The weed hosts of the pathogen should be eradicated.
 Crop sanitation- removing and burning the diseased leaves/ shoots etc.
 Deep ploughing in summer.
 Spray 0.8 to 1.0% B.M.or ridomil M-Z 0.2% after initiation of the disease.


Powdery mildew
3.Powdery Mildew :
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Erysiphe polygoni

Erysiphe crucifearum

Symptoms:

 Appear in the form of dirty-white, circular, floury patches on both sides of leaves and pods.
 Leaves surface covered with powdery growth of fungus resulting in drying.
 Affected plant produce small and shriveled seeds.

Management:

 Spray with Karathane @ 0.07 %
 Spray Wettable sulphur , Sulfex or Thiovet @ 0.3%


White Rust
4.White Rust:
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Albugo crucifearum

Symptoms:

 Local as well as systemic infections are noticed.
 Disease appear on leaves and characterized by the appearance of white creamy raised pustules on the under
surface of leaves.
 Corresponding upper surface become yellow.
 Pustules rupture and released chalky dust of spores (sporangia).
 Systemic infection causes hypertrophy and hyperplasia on inflorescences and pods.
 Affected flowers show malformation.

Management:

 Spray metalaxyl (ridomil MZ-72) or mancozeb @ 0.25 % or chlorothalonil (kavach) 0.2 %