Chilo suppressalis (Walker) or The Rice Stem Borer

Chilo suppressalis (Walker)

Common name:

The Pale-headed Striped Borer or The Rice Stem Borer or The Asiatic Rice Borer 

Order:

Lepidoptera

Family:

Pyralididae

Distribution:

India (Assam, West Bengal, Orissa and Bihar), China, Hawaii, Indonesia, Japan, Korea, Malaysia, Philippines, Taiwan, Thailand, South Vietnam, Spain, Formosa, Australia, Papua New Guinea and West Iran.

Host:

Rice, maize, millets and many wild grasses.

The freshly hatched caterpillar is about 1.2 mm long and has five grey brown linear dorsal strips on its body. When full-grown, it is 26 mm long and 2.5 mm wide. The head is yellowish brown. The middle dorsal line is lighter than the two along each side. The moth is 12 mm long, with pale yellow wings of 26 mm expanse. The male moth is smaller than the female

Life-cycle:

During the winter season the pest hibernates as larva in the stem or stubbles. The pupation takes place sometime in spring season which is followed by the emergence of moths. After mating, a female may lay about 300 eggs in masses of variable size on leaf blade near the tip or in the leaf sheath. The incubation period is 4-10 days. The freshly hatched larvae feed on the leaf sheath in groups. The second and third instar larvae move to the adjacent plants and bore into the culm through nodes. The larvae of second generation bore into the stem through the stalk of the penicle and travel downwards and reach the lower most part of the stem. The larval period is about 33-50 days. Pupation takes place within the rice stalk either near the middle or in the basal internodes. Pupal period lasts 5-10 days. Moth emergence starts in spring season. There are 1-4 generations in a year depending upon the weather conditions.

Damage:

The freshly hatched caterpillars first feed on leaf sheaths which show transparent patches. Later on, they make tunnel through the stem and feed on the soft tissues. When the feeding is inside the stem around the nodes, the stem becomes weak which is easily break down. The feeding in the central parts of young plants results in drying of central shoot or dead-heart' formation and white ears in the later stage of the crop.Two other allied species namely, Chilo indicus (Kapur) and Chilo infuscatellus Snellen have also been recorded infesting paddy in certain areas in India.

Control:

Same as mentioned under ‘Yellow Stem Borer', S.incertulas.