The citrus black whitefly, Aleurocanthus woglumi Ashby, is a common pest of "Dien" pomelo in Hanoi. The citrus black whitefly, A. woglumi went through various phases, such as eggs, three nymphal instars, puparium and imago. Females about 1.25 mm in length, males up to 1.05 mm long and has a slightly smaller size. Eggs of Aleurocanthus woglumi are usually laid on the underside of young leaves, attached by a short pedicel. The nymphs are staying mainly on lower leaf surfaces, can be found along the ribs of a leaf. The biology of citrus black whitefly, A. woglumi was studied individually in the laboratory at temperatures of 21.1-28.8°C and humidity 69.5-83.6 percent, using young leaves of "Dien" pomelo as food. The nymphal stage has three instars. The citrus black whitefly completes its life cycle in from 49.15 days to 70.34 days. A female may lay 100 or more eggs in her lifetime with hatching rate about 84.44 percent at suitable temperatures and humidities. The pest is most favoured by cool temperatures (optimum 25.6°C) and relatively high humidities (of 70-80 percent).