Symptoms and prevention of sawfly

In mustard crops there is a heavy attack of sawfly.
It is black in color, which damages the leaves quickly, it consumes the leaves, making holes on the sides of the leaves.
This skeletonizes mustard leaves .
To prevent this, spray Profenofos 50% EC @ 500 ml/acre or Thiamethoxam 12.6% + Lambda Cyhalothrin 9.5% ZC @ 80 ml/acre or Imidacloprid 30.5% SC @ 50 ml/acre