Study On The Arthropod Community Structure And Dynamics In Tobacco Field Of Jingxi County

The structural feature of the arthropod community including pests and natural enemies in tobacco fields of Jingxi County, Guangxi Province, was studied to provide a theoretical basis for the development of measures for insect pest integrated management and protection of natural enemies. The main results are summarized as follows:1. The arthropod community mainly consisted of leaf feeding, sap-sucking and rood feeding pests and their natural enemies, and other arthropod animals. Among11265arthropod specimens collected, a total of165species were recorded, belonging to3classes,13orders, and62families. Of these insects91species in2classes,10orders and36families were pests, accounting for54.49%of the total species, and76species in2classes,7orders and28families were natural enemies accounting for45.51%of the total species. Among natural enemies64species were predators and12species were parasitoids.2. Among insect pests, Loxoblemmus equestris, Myzus persicae, Velarifictorus micado, Teleogryllus mitratus and Opatrum subaratum were dominant, accounting for16.86%>16.81%、3.95%、3.24%and2.19%, respectively. The dominant natural enemy species were Cicindela raleea, Chlaenius pallipes, Calosoma maderae chinense, Pirata praedatoria, Pirata piratoides, Pardosa pseudoannulata and Trochosa ruricola. Depending on survey time, the dominant species of pests and natural enemies in tobacco fields differed..3. The tobacco field index of arthropod community characteristics is clear, at mature period of tabacco the diversity index was the highest (2.4869); at growth period, the community dominance was the highest (0.4267); at the root extending stage of tobacco, community evenness was the highest (0.7976). It is suggested that there are some richness and stability in the arthropod community of tobacco fields in Jingxi County. 4. Comparison and analysis of the arthropod community structure and dynamics of tobacco grown in the paddy field and dry land show that the composition of arthropod community differed between the two types of tobacco fields. The seasonal variations in dominant species in the arthropod community structure were obviou, but the dominant species between the two types of tobacco fields were different. At the root extending stage of tobacco, the dominant species of paddy type fields were Myzus persicae but spiders in the dry fields. During the period of actively growing of tobacco, the dominant species of paddy type fields was Opatrum subaratum but crickets in the dry-type tobacco fields. The arthropod community structure and dynamics of the two types of tobacco fields were different.5. Analysis of the population dynamics of Myzus persicae, crickets pests and spiders in tobacco fields of Jingxi County shows that main natural enemies in tobacco fields had a good control of main pests.