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Egg: Eggs are creamy white, flattened, oval and scale like and laid in mass. Each egg mass consists of 15-80 eggs and covered with buff coloured hairs. Before hatching, the eggs darken to a purplish tinge. They are laid mostly near the tip of the leaves.
Larva: The hatched larvae move downward and wander about on the plant for 1 or 2 hours. They may hang down by a sliver thread and get to other plants with the help of the wind. They can also swim over the water and reach other tillers. They enter the leaf sheath and feed upon the green tissues of the stem for 2-3 days. Then they bore into the stem near the node. Deposition of silica in the epidermal layer of the stem and leaf sheath acts as an obstacle to the first instar larvae to chew up a hole. Generally only one caterpillar is seen inside a tiller. It may come out and attack fresh tiller. The full-grown caterpillar measures about 20 mm, white or yellowish white in colour with a conspicuous prothoracic shield.
Pupa: Pupation takes place inside the rice stem, straw or stubble. Before pupation it make a exit hole in the internode and covers it will a thin web for the adult to come out later. The anterior extremity of the cocoon is tubular and attached to the exit hole and to make the cocoon waterproof the larva webs two horizontal septa in this tubular area.
Adult: They exhibit remarkable sexual dimorphism. The female moth is bright yellowish brown with a black spot at the centre of the forewing and a tuft of yellow hairs at the anal region. The male is small in size and brownish.