Mustard Fourth to fifth week practices

Mustard saw fly:

Symptoms:

Initially the larva nibbles leaves, later it feeds from the margins towards the midrib.
The grubs cause numerous shot holes and even riddle the entire leaves by voracious feeding.
They devour the epidermis of the shoot, resulting in drying up of seedlings and failure to bear seeds in older plants.
The yield losses are up to 5 to 18 %. In severe cases at the seedling stage, the crops have to be re sown.

Management:

Maintain clean cultivation
Applying irrigation in the seedling stage is very crucial for sawfly management because most of the larvae die due to drowning effect. Severe cold reduces pest load.
Collection and destruction of grubs of sawfly in morning and evening
Conserve Perilissus cingulator (parasitoids of the grubs), and the bacterium Serratia marcescens which infect the larvae of sawfly
Use of bitter gourd seed oil emulsion as on anti- feedant
Spray the crop with malathion 50 EC @ 1000 ml/ha quinalphos 25 EC @ 625 ml/ha. All this should be applied in about 600 to 700 litres of water per ha.

Downy mildew:

Symptoms:

Grayish white irregular necrotic patches develop on the lower surface of leaves.
Later under favourable conditions brownish white fungal growth may also be seen on the spots.
The most conspicuous and pronounced symptom is the infection of inflorescence causing hypertrophy of the peduncle of inflorescence and developing stag head structure.

Management:

Treat the seed with Apron 35 SD at the rate of 6 g/kg of seed before sowing.
Spray the crop with 0.2 % Ridomil or 0.1% Karathane as soon as the symptoms are noticed and repeat the spray two to three times at 10 days intervals.

Diamondback moth:

Symptoms of damage:

Whitish patches due to scraping of epidermal leaf tissues by young larvae
The leaves give a withered appearance but in later stages larvae bore holes in the leaves
It also bores into pods and feeds developing seed

Mechanical control:

Chemical control:

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