[Life table of Leptinotarsa decemlineata (Say) natural population and related affecting factors]

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.