Appearance and life cycle.

The eggs are round, initially green but turning reddish-brown over time. They are usually deposited singly, on the undersides of the leaves or occasionally, on the stems and petioles. The eggs are laid in early night, As the temperature drops and the humidity increases, the egg-laying increases. The caterpillars vary in colour from light to dark green, and hatch two to three days after the eggs are laid. The larval stage generally includes 5 or 6 instars but may include up to 8 instars. Caterpillars larger than 15 mm may be green or black and have three longitudinal white lines along the back and four pairs of abdominal legs, as well as a terminal pair. It loops as it crawls and is often confused with the small Soybean looper caterpillar (Chrysodeixis includens). The pupa is light green, turning a shiny, dark brown over time. The length of the pupal stage varies, depending on the temperature. The warmer the temperature, the shorter the pupal stage. The adult moth is greyish-brown. It has a characteristic line that runs diagonally across both wings. In conditions of high infestation or food shortages, its colour darkens. During the day, these months can be found in shaded spots, at the base of the plants. The life cycle is completed in 33 to 34 days, and there may be four or six generations per year.