| In order to understand the overall differences of arthropod community between the organic and non-organic fruit orchard, in order to provide people with a theoretical basis in the measures of controlling orchard pest.in this article,We use ecological indicators to analyze the characteristics of arthropod community structure between Wangjiayuan orchard which is an organic orchard and Beiliu orchard which is an non-organic orchard. These orchards locate in Beiliu village, Liucun town, Changping District, Beijing. At the same time, We also have a systematic and comparative analysis in diversity of them. The results are as follows:1.In these orchards,18088 arthropod speciments were gathered belonging to 2 class 13 orders.119 families were collected.in organic orchard,11953 arthropod speciments were gathered belonging to 2 class 13orders.112 families were collected.In the non-organic orchard,6135 arthropod speciments were gathered belonging to 2class 12orders.59families were collected. A total number of pest is 50 families, belonging to 9 orders.natural enemies is 44 families, belonging to 7 orders.3 orders,27 families is neutral insects.Many indicators of the organic orchard are apparently higher than the non-organic orchard. There are the number of arthropod, richness, diversity, evenness. But the dominance of the organic orchard is lower than the non-organic orchard. Due to the large effects of pesticides, in the non-organic orchard, species of arthropod community are too rare, diversity and evenness is low, the stability of community is poor. In two orchards, the main groups are Homoptera, Diptera, Hymenoptera, Coleoptera, and Lepidoptera. In all of them, the index of number, diversity, evenness and dominance is highest in Homoptera; the main dominant species are Aphis citricola.2. In nutrition structure of two orchards, the type and quantity of the herbivorous pests is dominant. The number of sucking insects is in a dominant position, the dominance of Homoptera insects is highest, the number of pests is large, just like Aphis citricola,Empoasca flavescens and other pests. Lepidoptera pests such as Lithocolletis ringoniella Matsumura,Lyonetin malivorella Matsumurn,Grapholitha molesta would cause a very great damage to orchard in a short time. In the organic orchard, the number of natural enemies is relatively high. These natural enemies have an important role in controlling the number of pests communities. The indexes of natural enemies of the organic orchard such as richness, diversity is more higher, the structure of community is more reasonable. In the organic orchard, Spiders are the dominant groups in natural enemies groups, in addition, the number of predators such as ladybirds,Chrysopa perla is also relatively large; the species of parasitic natural enemies are very rich. They can play a positive role in controlling the number of pests. Because of the frequent use of pesticides, in the non-organic orchard, people kill a large number of natural enemies of insects when we kill pests, at the same time, there is a greatly effect on the arthropod community structure.3.Impacts of six common germicides on mortality of the pest in organic apple orchard Aphis citricola and its natural enemy, Harmonia axyridis were tested. The results showed that all of the six germicides had toxicity to Aphis citricola whatever treated by spray or feed methods, however, the corrected mortalities were always less than 21%. The germicides did not increase mortality of larval H. axyridis treated by spray method or feeding with aphids treated by germicides. The above results indicated that the six germicides used in present study did not induce a high mortality to A. citricola and did not affect the mortality of H. axyridis either. A long time (1-3 years) the Pharmacy treated aphids feeding Harmonia axyridis has not a significant impact on the development duration.Therefore, we concluded that the using of germicide did not affect the insect community structure very much in apple orchard.
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