Grayak caterpillar (Spodoptera litura F., Lepidoptera, Noctuidae) is one of the most important pest, because it is polyphagic or has a wide range of hosts including soybeans, peanuts, cabbage, sweet potatoes, potatoes, and others. These pests often lead to decreased productivity and even crop failure because it causes the leaves to be torn, cut into pieces and perforated. If not immediately addressed then the leaves of plants in agricultural areas will be exhausted (Samsudin, 2008).
The young grayak (S. litura) caterpillar is greenish, while the instar caterpillar is finally brownish or dark gray and speckled with black and white stripes. Egg stages in this insect is for 3 days then continued with instar larvae I marked with a yellow larvae body with fine feathers, black head with a width of 0.2-0.3 mm, the length of instar I is 3 days . Followed by instar II larvae characterized by a green body with a length of 3.75-10 mm, the feathers are no longer visible and on the first abdominal segment there is a black line rising at the dorsal portion there is a white line extending from the thorax to the tip of the abdomen, to the thorax there are four points that march two or two, instar II is lasted for 3 days. Instar larvae III has a body length of 8-15 mm with a head width of 0.5 to 0.6 mm. On the left and right side of the abdomen there is a white zig-zag line and black sphere along the body, instar III is lasted for 4 days. Start instar IV color varies that is black, green, whitish, yellowish green or purplish green, body length 13-20 mm, instar IV last for 4 days (Utami et al., 2010)
Egg
Imago females lay eggs at night, eggs round to round oval eggs placed in groups on the surface of plant leaves. In one group the number of eggs is 30-100 eggs, the eggs can hatch within 2-4 days. The egg group is covered by fine white hairs, then the egg turns blackish at the time of hatching. Eggs generally hatch in the morning.
Larvae
The larvae of S. litura have varying colors, having black necklace or crescent on the fourth and tenth abdominal segments. On the lateral and dorsal side there is a yellow line. Newly hatched caterpillars are light green, dark brown or dark brown sides and live in groups. A few days later, the larvae spread by using a silk thread from its mouth. Usually caterpillars move to other plants clustered in large numbers. The color and behavior of the last instar caterpillars resemble caterpillars, a difference only in the crescent moon sign, dark green with dark elongated back line.
The development of early instar larvae mainly spreads to the tops of plants and leaves holes in the leaves and then into the leaf capillaries. The larval stage ranges from 9 to 14 days. The final instar larvae moves and falls to the ground and once inside the soil the larvae enter the pupae and then transform into pupa.
Pupa
Pupa S. litura is light brown and at the time of becoming imago turns into a blackish brown. Pupa has a length of 9-12 mm, dna berekpe obtek, pupa is in the soil with a depth of ± 1 cm, and often found at the base of the stem, sheltered under the dried leaves or under the soil particles. Pupa ranges from 5 to 8 days depending on the height of the place above sea level.
Imago
Imago has a length ranging from 10-14 mm with a span of 24-30 mm. The front wing is grayish white, in the center of the front wing there are three pairs of silver spots. The rear wing is white and on the edge is dark brown (Kalshoven (1981); Samharinto (1990)).source
I found this Grayak in the side yard of my house. on that page I plant some sugar cane trees. I have noticed it in the last few weeks. Starting from the caterpillar grayak was still small until now he has eaten almost out my sugar cane leaves.