Abstract: In this study, the life table of the 2nd generation of Leptinotarsa decemlineata (Say) natural population on potato plants was constructed based on functional factor life table method, and the control effects of different factors on the population were analyzed by exclusion analysis method. It was shown that the survival rate of eggs and first instar (79.1% and 69.3%, respectively) was rather lower than that of the L. decemlineata at other growth stages, suggesting that the eggs and first instar larvae were the key stages to control L. decemlineata. Among the controlling factors, “natural death” was the most effective factor, its exclusive index of population control (EIPC) being 187, “predators and others” was in the second place, with the EIPC being 1.51, while “parasitism” had no control effect. The index of population trend  of L. decemlineata would be increased 2.8 times if all natural factors were excluded. It was concluded that natural factors had a certain but weak action on the L.decemlineata population.

Key words: Leptinotarsa decemlineata, potato, natural population, functional factor, Xinjiang.