| This thesis came from the project"Special Fund of Anhui Province Governor (y47)—integrated pest management and application for the non-environment damage vegetables". Based on ecological investigation into arthropod community, the structure and the time and spatial dynamics of arthropod communities were analyzed and the interaction between main pests and its natural enemies were studied. These will provide theory foundation for IPM of pests lived in tomato fields.(1) The arthropod total community was divided into phytophage, predacious, parasitic - neutrality sub-community according to species nutrition and predator-prey relationship. Components of the total and each sub-community were analyzed by number of groups, individual numbers and some other ecological indexes. There was 15917 heads which belong to 36 species in spring - summer tomato fields. Pytophage sub-community included 15 species and its dominant species were Bemisia tabaci ,Adelgoidea and Frankliniella intonsa which relative abundances were 0.7546,0.1965,0.0409. Bemisia tabaci was dominant specie. Predacious sub-community included 13 species and its dominant species were Theridion octomacutatum, Erigonidiun graminicolum, Tetragnatha maxillosa and Orius similis which relative abundances were 0.6451,0.1364,0.0622,0.0553. Theridion octomacutatum was its dominant specie. There was 164585 heads which belong to 16 species in autumn-winter tomato fields. Pytophage sub-community included 9 species and its main species were Bemisia tabaci ,Adelgoidea,Chrysomelidae,Prodenialitura Fabr and Frankliniella intonsa which relative abundances were 0.9991,0.0006,0.0002,0.0001. Bemisia tabaci harm most. Predacious sub-community included 4 species and its main species were Saddle crab spider,Theridion octomacutatum, Erigonidiun graminicolum, Sitticus clarator which relative abundances were 0.5000,0.2000,0.2000,0.1000. In spring - summer and autumn-winter tomato fields, the main pests were Theridion octomacutatum , Erigonidiun graminicolum , Orius similis, saddle crab spider and Tetragnatha maxillosa by the method of comprehensive analysis. Dominant concentration and dominance in two crops were compared and the result indicated that phytophage sub-community>total community>predacious sub-community; The result of diversities indexes were predacious sub-community >total community> phytophage sub-community. The results of two crops above were the same, which was caused by large number of the dominant population.(2) Caused by interaction of pest with its natural enemies and climate factors, indexes of every community fluctuated up and down. Diversity index of total community change gradually, both total community and phytophage sub-community had low value because of the large individual number of Bemisia tabaci; while predacious sub-community kept in a high level all the time which shows natural enemies were in great charge of pests.(3) The relations between diversity indexes and other ecological indexes in every community were analyzed by Path analysis in two crops tomato fields. Diversity indexes H` had close relationship and great direct interaction with evenness J in total community; Richness R, species numbers S, dominant concentration C, dominance D all influenced diversity indexes by evenness J. Diversity indexes H` of phytophage sub-community had close relationship with evenness J in spring– summer tomato fields, but it was the most interaction with evenness J, richness R, species S in autumn– winter crops. The dominant concentration C had the greatest interaction with diversity indexes H`, then, evenness J, richness R. Diversity indexes H` of predacious sub-community in spring– summer was in great relationship to species numbers S and had great direct interaction, but it was great relationship to evenness J and had great direct interaction.(4) Total community in two crops in different time was analyzed by clustering analysis and optimization cut. The result revealed that the total community could be divided into 4 clusters when D is 0.954 in spring– summer crops and it was divided into3 clusters when D is 0.881 in autumn– winter crops. The clustering analysis results revealed the differences in the two crops and complexity of population in different periods.(5) The characteristic parameters of arthropod total community and its phytophagous,predacious sub-community in tomato fields in two crops were analyzed with the method of principal component analysis. The results showed that the contribution in the first principal component of arthropod community, phytophagous sub-community and predacious sub-community was 55.73%,62.99% and 74.74% respectively in spring– summer crops. For the three kinds of communities, the absolute values of normalized regressive coefficient of H'(diversity indexes) , J (evenness) and S (species numbers) were larger, indicating that H', J and S had greater contribution ; In spring– summer crop, the contribution in the first principal component of total arthropod community and phytophagous sub-community were 65.09% and 71.53% respectively. For the total arthropod community and phytophagous sub-community, the absolute values of normalized regressive coefficient of C,D,J and H ' had greater contribution.(6) In this present work, the quality, time and spatial framework of Bemisia tabaci and its natural enemies was further studied using stepwise regression analysis, grey system analysis, ecological niche analysis and aggregated-intensity index analysis of spatial patterns. The synthetic ranking analysis indicated that the main natural enemies of Bemisia tabaci were Erigonidium graminicda, Therdiong octomaculatum and Clubiana japonicola.The number of Bemisia tabaci during spring-summer and autumn-winter season in tomato fields was compared using T-test(t=3.3768, t>t0.01=2.86), which showed a highly significant difference. The average number of Bemisia tabaci during spring-summer season was 1086, while 14940 during autumn-winter season. During spring-summer season, the number and species of natural enemies inside the greenhouse was very few which was only 9 belonging to 4 species and it was 0.8% of the quantity of natural enemies during spring-summer season, for the greenhouse preventing natural enemies from entering.(7) The experimentation of control of Bemisia tabaci by using pesticides indicated that the control effect had the traits of quick and the control efficiency after 1d, 3d, 5d, 7d were 35.94%, 59.02%, 44.08%, 48.41%. It was showed that it was safe to the growth of tomato but poor for the control efficiency to the Bemisia tabaci. |
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