The cabbage whitefly Aleyrodes proletella L. (Hemiptera: Aleyrodidae) is a specialized insect that uses its mouthparts(stylets) to feed from the phloem of its host plants, which are found among the Brassicaceae and Asteraceae. Female whiteflies lay their eggs in circular patterns embedded in wax on the underside of the leaves. These were collected from the leaf of triangular lettuce, Crepidiastrum sonchifolium throughout the whole Chungnam province, 2013. We reared the cabbage whitefly on the egg-plant. The elongate-oval eggs are laid upright in a semicircle on the underside of Brassica leaves but didn’t in lab. Initially pale and translucent, the eggs become darker. Nymphs are scale-like and covered with wax; their color is white with two yellow spots on the abdomen. On the dorsal surface of the last abdomial segment is the vasiform orifice charactersitic of the group. The fourth instar is called the “pupa”. The pupa is thicker, immobile, and pale in color with red eyes. The adults are tiny, about 1.5 mm long, and moth-like. The head and thorax are dark. The abdomen is yellow and covered by a conspicuous white waxy layer. The forewings have a faint, dark bar. If disturbed, the adults fly readily. The duration of development of immature stages of Aleyrodes proletella decreased with increase in temperature, the mortality was higher below 16 ℃ and above 28 ℃.