About Mythimna separata (Walker, 1865)
Mythimna separata (Walker, 1865) has a wingspan ranging from 35 to 50 mm. Males do not have paired tufts on the ventral basal segment of the abdomen. Forewings are greyish yellow with either a dark-grey or reddish-yellow tinge. The round and reniform spots on the forewings are light or yellowish with indistinct edges; the reniform spot additionally has a white point at its lower margin. The external wing margin is darkened obliquely from the top backward, featuring a dark stroke and a row of dark points. Hindwings are grey, with a dark external margin. Antennae are thread-like. Eggs are spherical, milky white, and have a thinly reticulate surface. Larvae most commonly go through six instars, with seven instars occurring rarely. Final instar larvae reach 40 mm in length. The larva has two wide black-brown dorsal stripes and one lighter intermediate dorsal stripe, plus a black-brown lateral stripe along the spiracle line. Spiracles are brown with black rims. Pupae are yellowish brown and shiny. In terms of ecology, adult moths fly from January to April, with the exact flight period varying by location. Larvae feed on a variety of agricultural plants including Zea mays, Sorghum bicolor and Oryza sativa, so the species is considered an agricultural pest. Caterpillars of this species do not feed on Momordica charantia, due to the presence of the triterpenoid glucoside momordicine II, a natural inhibitor of caterpillar feeding on this plant.
