Abstract: The spiralling whitefly, Aleurodicus dispersus Russell, is a newly destructive invasive pest in Hainan Island, China. The morphology and biology of the spiralling whitefly were studied systematically through observations and experiments both in fields and laboratory. The results showed that the developmental threshold and the effective accumulative temperature for whole generation were estimated to be 8.88℃ and 511.86 degree-days, respectively, and 8-9 generations could occur per year in Hainan Island. In the temperature range of 18℃ to 32℃, the developmental duration from egg to adult is 26.63 to 57.15 d (including that for egg 7.15-15.93 d, 1st instar nymph 4.00-11.03 d, 2nd instar 3.83-7.53 d, 3rd instar 4.09-8.64 d and 4th instar 7.56-14.03 d), but the whitefly failed to survive at 14℃. The temperature higher or lower than 28℃, however, displayed negative effects on the population increase of the whitely. The adults are normally active at dawn and dusk, especially at calm, uncloudy dawn (7:00 am) or in the cloudy morning (9:00 am), but mostly inactive in rainy day.

Key words: Spiralling whitefly (Aleurodicus dispersus), biological characteristics, morphology, developmental duration, developmental threshold, effective accumulative temperature, life table