ABSTRACT The number of generations of woolly whitefly [Aleurpthrixus floccosus (Maskell)] was determined on sweet orange orchards [Citrus sinensis (L.) Osbeck] in the Pica Oasis, Tarapacá Region, Chile. The essays lasted one year, from April 2010 to April 2011. Woolly whitefly presented 7 generations in the Pica Oasis, which overlap causing the constant presence of this pest in Pica. In the coldest months (autumn-winter) the cycle tends to be longer (65.5 days), while in the warmer months (spring-summer) the cycle lasts 45.5 days. In general, the cycle is completed at 52 days.