| This article by investigate two different methods of cultivation of rape fields of the whole growing field in Feidong region,not only studying rape fields of arthropod community structure and dynamics of community characteristics,but also studying the pest and natural enemies of the sub community of structure and their respective dynamics of dominant population;and comparing different methods of cultivation of rape fields of arthropod community structure by analyzed the data,and getting my own views.Through field systemic investigation and predacious function of experiments about natural enemies and the pest of dominant population indoors,evaluating the function of the Natural Enemies' controlling the pests.For the purpose of the basis of making full use of natural enemies to control the biological function.The main conclusion is as follows:1.Rape Field arthropod community structure and dynamics1.1 The total of arthropod community structure and dynamics in rape fieldThere are 55 species of arthropod,belonging to 2 classes.10 orders.39 families, including pest 7 order.19 families.28 species,natural enemies 6 order.15 families. 22 species,neutral insects 3 order.4 families.4 species,in Feidong region rape fields. Rape of direct seeding fields arthropod 53 species belonging to 38 families,of which 28 species of insects,21 types of enemies,Neutral four species of insects.Rape of transplanting fields arthropod 53 species belonging to 38 families,of which 28 species of insects,21 types of enemies,Neutral four species of insects.In the entire growing period, the same of change between the species diversity,evenness and richness,but the dominant concentration are showing the opposite trend.Generally speaking,the Fields dominant concentration were greater than broadcast fields,and diversity and uniformity are less than them.1.2 The studying of the pests sub community structureThe species richness between direct seeding fields and transplanting fields is same, and the species diversity and evenness more 7.3%and 8.9%than transplanting fields.That is relatively,there are not proEecting dominant species in direct seeding fields of sub community during investigating rape fields.There is not significant effect on pests' vertical distribution of different cultivation methods,and the plant species on the distribution is similar.1.3 The studying of the natural enemies sub community structure The kinds of sub communities of natural enemies are 6 orders.15 families.22 species,which predatory insects 4 orders.7 families.10 species,araneae 9 families. 11 specie,and a parasitic insect species.Spiders are proEecting dominant species in two types of rape field ecosystem advantages natural enemies,there are not greatly differ in two rape fields enemies quantitative structure,and they have much of similarities in species of composition.In quantitative composition analysis,heterochromatic ladybug is dominant species in predatory insects,and theridion octomagu and erigonidiurn gramim are dominant species in Spiders,in rapeseed fields enemies communities.There is not significant effect on natural enemies' vertical distribution of different cultivation methods, and the plant species on the distribution is similar.The similar trends between the sub community of species of Natural enemies of arthropod and the entire community with the time changed,shows species richness of the "M"-type changes,the species change of trend is increase-descrease-increase-descrease. There is clear correlation between the natural enemies and pests in time.It is no basic difference between the natural enemies of the two fields.With previous conclusions,the individual pests of happening is relatively easy in transplanting fields than direct seeding fields,which is stable.Therefore,the communities are more stable and advantage of control pests by natural enemies,in direct seeding fields.2.Natural enemies of pests control Study2.1 Qualitative research of field investigationThe number of pests,in transplanting field,increase to peak over direct seeding fields',but them decrease slower than direct seeding fields',the number of natural enemies are uniform with pests on the trend of increase and decrease,and the time of reach the peak,in direct seeding fields,is later than in transplanting field.In addition,the fluctuations obviously different between the number of natural enemy communities andThe number of pests,in rape fields.In general the number of pests in autumn and winter are peak,but it is the highest volume that natural enemy communities in April.So, by technology of ecological control,pest control measures,the best of use of biological control measures in pre-control,sustainable development of natural enemy communities, and natural enemies controlling play potential,reduce environmental pollution,and to achieve sustainable pest control,such as sexual attractants.Bt(Bacillus thuringiensis),and so on.Since the late natural enemies control factor in the results,pest level is very low and rarely cause economic losses,normally not control application. Aphids(Myzus persicae and Lipaphis erysimi)are the most important pest,they are occurs in the whole growth period of rape.Two kinds of the natural enemies are highest frequency in the rape fields,theridion octomagu and erigonidium gramim,the occurs of time lag between the natural enemies and the pests in transplanting fields,but the same of trend,in direct seeding fields.In short,theridion octomagu and erigonidium gramim,are important natural enemies by used control aphids,and be propectted,for the control of pests in the late create conditions for development.2.2 Quantitative studies in laboratoryLeis axyrids of adults' predators function coincidence Hollingâ…¡model,its functional model for Na=1.0215N/(1+0.00406 N),in 24h,its the theoretical maximum amount of predation 251.89.Propylaea Eaponica of adults' predators function coincidence Hollingâ…¡model,its functional model for Na=0.9744N/(1+0.0043 N),in 24h,its predator theory of the largest amount of 232.08.Leis axyrids more Propylaea Eaponica. |
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