Analysis And Study On Influence Factors Of Aphid Populations Based On Structural Equation Model

In the agricultural ecosystems,the growth of aphid populations is closely relevant to meteorological eco-factors(such as air temperature,atmospheric rainfall,air humidity),biological eco-factors(such as plant cover,insect dynamics).It is important to study the influence of the eco-factors on aphid populations.What is the influence of the factors on aphid populations? What is the degree of influence on aphid populations? Structural equation model is a useful tool to solve these problems.Based on the theory model of structural equations,the corresponding structural equation model with the meteorological and biological eco-factors is established using the 32-year survey data of wheat aphid ecosystem in the experimental plot near Northwest Agriculture and Forestry University.The wheat aphid populations dynamics in different environments and months is revealed,which provides the theoretical basis for pest management.The specific contents are as follows:1.According to ecological principles,the theory models of structural equations of aphid populations are established,on the one hand,the relevant survey data of the meteorological eco-factors in different months(such as March,April and May)is used to fit the model and to investigate the influence of meteorological eco-factors on the wheat aphid population dynamics by AMOS24.0.On the other hand,the relevant survey data of the biological eco-factors in different months(such as March,April and May)is used to fit the model and to investigate the influence of biological eco-factors on the wheat aphid population dynamics.2.Based on the existing theory model of structural equation of aphid populations,the humidity in the meteorological eco-factors has minor influence on aphid populations compared with temperature and rainfall;Similarly,the syrphidae populations and ladybug populations in the biological eco-factors have a greater influence on the aphid populations compared to spiders populations.Based on the above,the reduced model of aphid populations is proposed to analyze the wheat aphid population dynamics.On the one hand,thesis broadens the application of structural equation model;on the other hand,it provides a new view for the pest management.