Studies On The Dynamics Of The Arthropod Communities In Tobacco Fields And The Interaction Relationship Between Myzus Persicae And Its Natural Enemies

The thesis reviewed international research progress on arthropod community in agricultural fields in recent years. The developing strategies of research on arthropod community were summarized, combined with integrated pest management. The dynamics of the arthropod communities in tobacco fields and the interactions of the Myzus persicae with its natural enemies were studied. The researching results were as follows: (1) The arthropod communities in tobacco fields were divided into four sub-communities, which are phytophages, predators, parasitoids and neutralities. The structure and dynamics of the arthropod communities and different sub-communities were analyzed by using a number of community parameters in the fields of Nc89, Nc82 and K326 tobacco varieties. The results indicated that there were 76 species of arthropod belonging to 55 families in three tobacco fields. The relative abundance of ph~rtophages and predators were 0.6469?.8218 and 0.1237?.3060 respectively. The dominant species in phytophages and predators sub-communities in three fields were almost the same. Dominant concentration of the arthropod community in the Nc89 was larger than that in the Nc22 and K326. The diversities of the artbropod community in three fields were compared by different indices. It was found that the DO index order was Nc82>K326>Nc89, and that was superior to others in analyzing the diversity of different arthropod communities. This suggested that the possibility of pest outbreak in Nc89 field was larger than in others. The dynamics of the diversities (H? and evennesses in phytophages sub-communities and arthropod communities in three fields was almost the same, which changed from loosely to highly tended, to loosely, and then, to highly tended again. And that of the predators sub-communities changed from highly to loosely tended, and then, to highly tended again. The diversity was a function of species richness and evenness. The main component affecting diversity was species evenness, which accounted for 75.90?7.83% of the variation in diversity in three fields. (2) Application of Diamethoate gave little effects and Qrthene gave some effects to number of group in arthropod community in tobacco field. Application of Diamethoate and Orthene gave some effects to number of individual in arthropod community. In the action of pesticide, the diversity levels of arthropod community in the D treatment plot had a significant increase. The increasing degree of diversity in arthropod community in the 0 treatment plot was smaller than in the D treatment plot. Applieation of D and 0 gave some effects to number of group in phytophages and predators. The declining degree of number of group in phytophages in the D treatment plot was larger than in the 0 treatment plot; and in predators in the D treatment plot was smaller than in the 0 treatment plot. The declining degree of number of individual in phytophages in the D treatment plot was larger than in the 0 treatment plot. The increasing degree of diversity in phytophages in the D treatment plot was larger than in the 0 treatment plot; and in predators in the D treatment plot was smaller than in the 0 treatment plot. (3) The effects of Imidacloprid on the arthropod community and different sub-communities were studied. The results showed that the increasing degrees of diversity indices and numbers of group were larger in phytophages than in predators, application of I in the earlier stage of tobacco growth. Diversity indices and number of group in phytophages and predators had a certain degree declin...