Studies On The Dynamics Of Arthropod Communities And The Disturbance Of Pesticide In Soybean Field

This thesis came from the project "Special Fund of Anhui Province Governor(y47)—integrated pest management and application for the non-environment damage vegetables",strived to discover the traits of arthropod community in soybean field and enrich the theoretical foundation for IPM of pests.(1)The arthropod total community was divided into four sub-communities:phytophage, predacious,parasitic and neutrality sub-community as to species' nutrition and predator-prey relationship.Components of the total and every sub-communities were analyzed by number of groups,individual numbers and some other ecological indexes.In 2005,arthropods got 59 species which belonged to 47 families,phytophage was prominent part,its relative abundance was 0.8397,dominant species was Aphis laburni;and that of predacious sub-community was 0.1798,dominant species was Therdion oslumaculatum;In of 2006,arthropods got 52 species belonged to 48 families,phytophage was prominent part, its relative abundance was 0.8794,dominant species was Aphis laburni and Bemisia tabaci;and that of predacious sub-community was 0.0883,dominant species was Misumenops tricuspidalus;Dominant concentration and dominance in two years were compared and the result was phytophage sub-community＞total community＞predacious sub-community,and result of the diversities indexes predacious sub-community＞total community＞phytophage sub-community;The result of the above in two years was same,which was caused by large number of the dominant population.(2)Caused by interaction of pest,natural enemy and climate factors,indexes of every communities fluctuated.Change tendency of diversity index in two years in total community was:low-high-low-high-low;and so did phytophage sub-community,while predacious sub-community kept in a high level all the time.(3)The relations between diversity indexes and other ecological indexes in every communities were analyzed by Palb analysis in two seasons.Evenness had close relationship with diversity indexes in total community;richness,species numbers, dominant concentration,dominance all influenced diversity indexes;diversity indexes of phytophage sub-community was decided by evenness,and so did predacious sub-community.(4)Total community and phytophage,predacious sub-community in two years in different time were analyzed by clustering.The result in 2005:The total community was divided into 4 clusters when D is 1.48;so did the phytophage when D is 1.87;the predacious was divided into 4 clusters when D is 1.29.And the result in 2006:The total community was divided into 4 clusters when D is 1.49;so did the phytophage when D is 1.89;the predacious was divided into 4 clusters when D is 1.26.The clustering result of the optimization partitions in the arthropod total communities in 2005 was 6.27,8.21～9.20,9.30～10.10,10.20;which in 2006 was 6.9～7.7,7.14～7.28,8.4～8.11,8.18.(5)The characteristic parameters of arthropod community and its phytophagous, predacious sub-community in soybean field in two years were analyzed with the method of principal component analysis.The results showed that in 2005:in the first principal component,the contribution of arthropod community,phytophagous sub-community and predacious sub-community in soybean was 71.49%,59.53%,64.47%respectively.For the three kinds of communities,the absolute values of normalized regressive coefficient of N (number of individual),N₁(Hill diversity index),N₂(Hill diversity index)and S(species numbers)were larger,indicating that N,N1,N2 and S had greater contribution;in 2006: in the first principal component,the contribution of arthropod community,phytophagous sub-community and predacious sub-community in soybean was 71.98%,68.70%,78.97% respectively.For the three kinds of communities,the absolute values of normalized regressive coefficient of N,N₁,,N₂,S had greater contribution.(6)In order to carry out the integrated pest management for the non-environment damage vegetables,and analyze the effect of IGR and plant pesticide on the arthropod community, insect pest and their natural enemies,the studies of the effect of emulsion of 0.3% Azadirachtin,KKY and IGR on the total arthropod community and its Pest communities and Natural enemy communities in soybean were conducted systematically in 2005 and 2006.The result showed that the two kinds of plant pesticides gave an important influences on the number of species and individuals of Pest communities and Natural enemy communities after four days with application.So did Chlorfenapyr except for the natural enemy community in 2005.And so did it in 2006.The effects of the three kinds of pesticides on the richness of species R,the dominant concentration C,the diversity index of Shannon-Wienner and Hill's N₂,the evenness J etc of the arthropod community and its sub-communities were not significant comparing with the control plot.The stability of community in the three treatment plots was better than control plot,especially emulsion of 0.3%Azadirachtin plot was obviously better than control plot.(7)Bemisia tabaci was the main pests in soybean field,Control effect of three kinds of pestcide on the tobacco white fly showed that adjustment decrease rate was 46.49%,54.33%,46.39%after one day with application; that of 0.3%Azadiraehtin added bamboo vinegar fluid was 95.44%,and that of KKY added bamboo vinegar fluid was 99.35%,and that of IGR added bamboo vinegar fluid was 95.44%after twenty days.