The blackheaded caterpillar larva live in galleries on the lower surface of the leaves and feed on the chlorophyll containing parenchymatous tissues resulting in loss of photosynthetic area. Appearance of green and dried up   patches interspersed on the upper epidermis of leaves and presence of larval galleries and pupal cases on the abaxial surface of leaves. In severe cases of infestation the whole plantation presents a scorched appearance.

Egg to adult period is completed in 2 to 2.5 months; nearly 42 days is spent as larva. The fully-grown larva is about 15mm long, light green  with reddish brown stripes   and with a black head.  It pupates in silken cocoons   in the larval gallery; the   adult is a   grayish moth measures   10—15 cm long with   a wing spread   of 20-25mm. The total  duration of the pest   from egg to adult  is completed in about two months.