Adults of the European pepper moth (Duponchelia fovealis) are light to dark brown with a clearly visible white crinkled line on the forewing. The end of the remarkably long abdomen bends upward almost vertically, with the abdomen of males often being longer than that of females. Another distinctive feature is the triangle formed by the head and forewings. Moths mainly fly at night, but can sometimes be seen in the daytime.
Eggs are laid singly or in groups of 5 to 10 eggs, overlapping in a tile-like fashion on both the upper and lower surface of leaves close to the veins, or low on the stem or stalk close to the ground. The pinkish red eggs are about 0.5 mm in diameter and become steadily darker. Just before hatching, which occurs about a week later, the young larva is visible within the egg. The full-grown caterpillars are 20 to 30 mm long and have a creamy white colour. Along the dorsal surface of the body there are pairs of dark dots. The dark head is also conspicuous, as are the four dark dots behind the head capsule. There are 4 pairs of prolegs.
Caterpillars are found in webs, preferably in damp, humid places and are thus mainly found low in the crop, often in decaying organic material on the ground or substrate. They feed on detritus as well as life materials. Young larvae feed on the leaves and flowers before they bore and burrow into the stem to emerge at ground level. The caterpillars pupate in an earthen cocoon, concealed either within the crop or in another suitable spot in the vicinity. Pupation occurs in a cocoon made of webbing, frass and soil particles. The pupa itself is yellow-brown, becoming darker as the adult gets closer to emergence, and measures 9 to 12 mm.