| Previous distributions of Bemisia tabaci (Gennadius) were limited to regions between tropical and subtropical zone. However, the pest in virtue of flower and other economy crops and young plants has invaded rapidly every continent in the world except Antarctica, along with the worldwide commercial trade. B. tabaci has become one of the most important pests of the vegetable, cotton, many ornamentals and other economy crops. Therefore, the host range and the occurrence of B. tabaci were investigated from 2002 to 2004 in Jiangsu province. It was analyzed that the selection and suitability of B. tabaci to different hosts and the different varieties (strains) of the vegetable, and the part ecological characteristics of B. tabaci and Trialeurodes vaporariorum Westwood was compared in this paper. The main results were as follows.1. The results of the investigation showed that the hosts of B. tabaci in Jiangsu province include 162 species or varieties belonging to 45 families, and most of them belonged to families Compositae, Solanaceae, Cucurbitaceae, Cruciferae and Leguminosae. The occurrence degree of B. tabaci at the different regions of Jiangsu was the degree of the North > the degree of the Center > the degree of the South.2. The analysis of the host suitability for B. tabaci at Yangzhou area indicated that cucumber, kidney bean, cauliflower, eggplant, cabbage, squash and lettuce etc. were the most suitable hosts, and greengrocery, cowpea, radish, agarics, green soy bean and haricot bean etc. were the suitable hosts, and capsicum, Coriandrum sativum, Ipomoea aquatica, Lactuca sativa L. var. crispa, pea etc. were the common hosts, and amaranth, spinach, carrot etc. were the subordinate hosts.3. The results of the investigation in 2002 and 2003 showed that the emergent time of B. tabaci on the outdoor vegetables was in the last ten day of May, and disappeared gradually in the middle or the last ten days of December. The occurrence of B. tabaci was ten generations per year, and the peak of the population appeared in the last ten days ofAugust or the early and middle of September.4. The selection and suitability of B. tabaci B-biotype to cucumber, eggplant, tomato, capsicum, cowpea, lettuce, cotton and Humulus scandens indicated that cucumber and eggplant were the favorite hosts which were the most suitable for the growth, development and reproduction of B. tabaci, and capsicum was the unsuitable hosts for the pest.5. The selection and suitability of B. tabaci B-biotype to different varieties (strains) of the same hosts showed that the pest prefered some varieties (strains). For example, (1) among the twelve cowpea varieties, B. tabaci adults had the preference to Ningjiang No.3, and had the highest fecundity on it, and Bangda No.l to the contrary. The development duration for the pest on Ningjiang No.3 was the shortest, but the longest on Qiuadjiang. The total survival from egg to adult on Zhijiang30 was the lowest, and the highest on Ningjiang No.3. The order of population trend index (I) of the pest on the different varieties was Ningjiang No.3> Yangjiang40> Chunqiuhongjiangdou> BangdaNo.1> Zhijiang30, so we concluded mat Ningjiang No.3 was the most suitable host for B. tabaci to growth, development and reproduction. (2) Among the fourteen eggplant varieties (strains), B. tabaci had the very preference to Heimazichangqie and the nonpreference to Longqie No.1. The survival and the reproduction exhibited also significantly difference, and the highest fitness on Longqie No.1, and the lowest fitness on Liaoqie No.3. The development duration for the pest on Liaoqie No.3 was the shortest, but the longest on Xuzhouchangqie. The population trend index (I) of the pest on three eggplant varieties was presented in the following order, Sunqiqie>Yangqie No.1>Ziyuanqie. (3) Among the fourteen tomato varieties (strains), B. tabaci had the preference for Shanghai908F1, and the nonpreference for DRK476 and EA. The survival and the reproduction exhibited that the highest fitness was on Hezuo906F6, and the lowest fi...
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