The most susceptible stage for the disease
development is the flowering stage.
Symptoms appear on all aerial parts but usually
on leaves and inflorescence.
Grayish white irregular necrotic patches
develop on the lower surface of leaves.
The most conspicuous and pronounced
symptom is the infection of inflorescence
causing hypertrophy of the peduncle of inflorescence.
The affected inflorescence does not produce
any siliqua or seed.
The extent of damage is 17-32 % in mixed
Survival & Favourable Conditions
The pathogen survives as oospores on the
affected plant tissues and on weed hosts.
Cool (10-20 C temp) and wet weather (90%)
humidity favours disease development.
Destroy the diseased crop debris.
Follow at least three years crop rotation.
Varieties of Brassica napus group are resistant to this
Timely sowing between 10 - 25th October.
Use healthy certified seeds.
Field sanitation is a must.
Destruct the crop residues.
Application of potash in recommended doses reduce disease
Seed treatment with 6g Metalaxyl (Apron) per kg seed
single spray with Metalaxyl (Ridomil MZ) at 2.5 g/litres at 60
after sowing is effective in managing the disease.
Spray the crop with Mancozeb 75 % W.P. at the rate of 2 gm per
litre of water at the onset of the disease.
Repeat the spray after 15 days interval.
Apply potash in recommended dose.
Seed treatment with Apron-35, followed by first spray of Ridomil
(0.25%) at 60 days after sowing and second and third sprays of
Rovral (0.2%) at 80-100 days after sowing provide effective