Cassava pink mealybug (Phenacoccus manihoti) invaded Vietnam in 2012 in Tay Ninh province and cause severe miniskirt on cassava. September 2014 they appeared and harmed to cassava in Phu Yen province. Biological characteristics of the cassava pink mealybug was studied under laboratory conditions in Phu Yen at temperature of 27.76oC, 30.72oC and 68.04%, 80.16% RH using cassava plants and leaves as food. The male of cassava pink mealybug was not recorded. The nymphs have 3 instars, duration of instars was from 4.07 days to 6.69 days, the pre-oviposition period was from 4.68 days to 6.96 days. The life cycle was 30.45 days with fed by cassava leaves and 31.08 days fed by cassava plants at 27.76oC, 80.16% RH
the life cycle was 28.67 days fed by cassava leaves and 28.18 days fed by cassava plants at 30.72oC and 68.04% RH. Fecundity of cassava pink mealybug which fed on cassava plants was significantly higher than those fed on cassava leaves. Each female fed on cassava plants laid 318.1-343.67 eggs, a female fed on cassava leaves laid 103.75 to 150.2 eggs. In Phu Yen province, the cassava pink mealybug has about from 11 to 12 generations, duration of the shortest one was 25 days and the longest one was 39 days, in which the generations of May to Ausgust was the most important.