The Population Dynamic State And Community Mechanism Of The Outbreak Of Ceroplastes Japonicus In Jujube Orchard

Major: Forestry Protection Research Field: Entomological EcologyMaster Candidate: LIANG Yin-quan Supervisor: Prof. GAO Bao-jiaJujube tree is peculiar to china. Ceroplastes japonicus is an important pest imperil Jujube. The study of it's population dynamic state - spatial distribution and community mechanism of it's outbreak are theoretic basis for the ecological control of Ceroplastes japonicus .In this research ,6 jujube orchards in different habitat condition were selected . The population dynamic state >. spatial distribution of Ceroplastes japonicus and characteristics of the plant community -. insect community and landscape in different jujube orchards were being investigated and analyzed. The results are as follows:In different plots, the spatial pattern of female and nymph Ceroplastes japonicus is aggregating distribution. The aggregation degree is assumed to be dependent to the population density.The trend of annual change of population quantity is gradually lifting from April to July, and beginning to descent in July. The outbreak degree in different plots from heavy to light are Guangzongl > Guangzong2 > Zhangma> Huangdiangou > Xianrencun > Xiyangzhai.The trend of nymph population dynamic state is aggregating at the beginning, then diffusing rapidly. The population diffusing periods are before and after the peak of the hatching period.The outbreak degrees in different part of the jujube tree crown from heavy to light are south >east > west >north, upper >lower, outer > inner, in different branch age, land 2 year old branches' population outbreak heavier than perennial branches'. The 30-year-old jujube trees have the largest population in different age trees. The stronger trees have the lower population outbreak degree. With the high level cultivating management the50population outbreak lightly.The annual change of the insect communities' diversity homogeneity and dominance are different among the plots. By the community similarity coefficient, the plots can be classified into plain and hill two classes. In the plain plots, the dominance of Ceroplastes japonicus is higher. In the hill plots, the dominance of Ceroplastes japonicus is lower. The characteristics of insect community' are obviously correlated with the outbreak degree of Ceroplastes japonicus.The composition and diversity of the plant communities are different among plots. By the community similarity coefficient, the plots can be classified into plain and hill two classes. In the plain plots, crops are essential species, the Ceroplastes japonicus heavily outbreak. In the hill plots, wild plant species are abundant, the Ceroplastes japonicus outbreak lightly. The characteristics of plant community are obviously correlated with the outbreak degree of Ceroplastes japonicus.The landscape diversity is different in plots. In the plain plots the landscape component types are monotonous, mostly are farmlands, and the Ceroplastes japonicus outbreak heavily. In the hill plots, the landscape component types are abundant, and the Ceroplastes japonicus outbreak lightly. The landscape diversity is obviously correlated with the outbreak degree of Ceroplastes japonicus.The insect community heavily influences the outbreak degree of Ceroplastes japonicus, and the influence from landscape and plant community are lighter. The insect community' is necessarily correlated with the landscape and plant community, the integration effect and mechanism of their influences on the outbreak degree of Ceroplastes japonicus need to be studied further.Keywords:Ceroplastes japonicus;population;community mechanism;diversity;landscape50population outbreak lightly.The annual change of the insect communities' diversity homogeneity and dominance are different among the plots. By the community similarity coefficient, the plots can be classified into plain and hill two classes. In the plain plots, the dominance of Ceroplastes japonicus is higher. In the hill plots, the dominance of Ceroplastes japonicus...