Studies On Bemisia Tabaci(Gennadius) On Cotton In Jiangsu Province

Bemisia tabaci(Gennadius) is cosmopolitan pest, usually outbreak and plagued in many areas in the world. The research result currently shows: Bemisia tabaci(Gennadius) is a fast evolution complex species which include 12 genetic group and 24 populations have specific biotype name. Due to the wide hosts, stronger reproductive ability, overlapping generations and long time chemical pesticide control, Bemisia tabaci(Gennadius) has strong resistance and very hard to control. So we monitor the biotype and resistance of Bemisia tabaci(Gennadius) in JiangSu province, hope to know its biotype and resistance level and supply scientific foundation of reasonable way to use pesticide. At the same time, we study on its population dynamic, selectivity and adaptability in different cotton variety, in order to supply foundation of Integrated Management to Bemisia tabaci(Gennadius). All the study results as follows:1. Using RAPD molecular marker technique and mtDNACOI gene sequence to detect the biotype of Bemisia tabaci(Gennadius) in JiangSu province. The result shows: it is B-type in five regions and Q-type in two regions which detected in seven different cotton fields in 2005; B-type in five regions and Q-type in seven regions which detected in twelve different cotton fields in 2006. In 2007, deteted 11 different cotton fields of B. tabaci biotype and all of them were Q-type except QiDong county and RuDong county. All this results proof Q-type is replace B-type progressively and become main biotype in cotton field in JiangSu province.2. Study on the population dynamic of B. tabaci in 10 different cotton variety. The results are as follows:(1)B. tabaci endanger seriously in most cotton varieties in GaoYou County in 2006, At the end of August the population number went up, at the beginning of October it has a small peak and in November there is a the highest peak. In YangZhou outskirts cotton fields, the B. tabaci endanger degree is light, at the middle or the end of Sep. the population number gone up, at the beginning of October it has a small peak, after that the population number in different cotton variety has highest peak in succession. In GaoYou County, the cotton variety of Sikang NO.3 and Sumian NO.22 have the highest pest population number, there are 23.7953 each cm2 and 23.5851 every cm2, but in Xiangzamian NO.3 the population average number is minimum, only 12.4601 each cm2. The difference between different cotton varieties was extremely significant. In Yangzhou region, the pest population in Keming NO.3 is obvious higher than other cotton varieties and in Xiangzamian NO.3 is minimum. It proofed that the insect-resistance of Sikang NO.3,Sumian NO.22 and Kemian NO.1 is weak, and the insect-resistance of Xiangzamian NO.3 is strong.(2)The endanger degree of B. tabaci in Gaoyou County in 2007 is weaker than in 2006. In most cotton varieties, the population of B. tabaci gone up at the beginning of August, has a small peak at the beginning of September, has a big peak at the end of September. Furthermore, the year average pest population on Simian NO.3 and Zhongmian NO.29 is highest, reach respectively 6.2874 each cm2 and 6.2295 each cm2. But the pest population on Xiangzamian NO.3 is smallest, only 3.6316 each cm2.3. Study on adaptability of B. tabaci in different cotton variety, the results as follows: the selectivity in 10 different cotton variety of the first and second generation B-type B. tabaci has some difference also include developmental periods, survival rate of each life stage, longevity of the female and the number of eggs laid. They have strongest selectivity on Zhongmiansuo NO.29 and Sumian NO.22, but the second generation of B. tabaci had higher fitness of survive and reproduce which means this two cotton varieties have weakest insect resistance. They have weakest selectivity on Xiangzemian NO.3 and Siza NO.3, lower fitness of survive and reproduce which means strong insect resistance.4. The results of resistance of B. tabaci(Gennadius) in some cotton regions are as follows: The level of resistance of Q-biotype Bemisia tabaci(Gennadius) on cotton in DongTai to imidacloprid,abamectin,deltamethrin,buprofezin and acetamiprid is higher than in GaoYou. In DongTai: The level of resistance of adults of Q-biotype B. tabaci on cotton to imidacloprid is the highest(13.30-fold), The level of resistance of that to buprofezin is the lowest(1.70-fold); The level of resistance of eggs of Q-biotype B. tabaci on cotton to buprofezin is the highest(6.92-fold), The level of resistance of that to deltamethrin is the lowest(1.59-fold); The level of resistance of 1~2 instar of Q-biotype B. tabaci on cotton to imidacloprid is the highest (27.86-fold), The level of resistance of that to deltamethrin is the lowest(4.13-fold); The level of resistance of 3~4 instar of Q-biotype B. tabaci on cotton to acetamiprid is the highest(7.4-fold), The level of resistance of that to abamectin is the lowest(2.81-fold); The level of resistance of pupa of Q-biotype B. tabaci on cotton to acetamiprid is the highest(6.77-fold), The level of resistance of that to imidacloprid is the lowest(2.18-fold). In GaoYou:The level of resistance of adults of Q-biotype B. tabaci on cotton to imidacloprid is the highest(7.15-fold), The level of resistance of that to buprofezin is the lowest(1.58-fold); The level of resistance of eggs of Q-biotype B. tabaci on cotton to abamectin is the highest(6.26-fold), The level of resistance of that to deltamethrin is the lowest(1.22-fold); The level of resistance of 1~2 instar of Q-biotype B. tabaci on cotton to imidacloprid is the highest(9.55-fold), The level of resistance of that to deltamethrin is the lowest(2.33-fold); The level of resistance of 3~4 instar of Q-biotype B. tabaci on cotton to buprofezin is the highest(3.05-fold), The level of resistance of that to abamectin is the lowest(1.50-fold); The level of resistance of pupa of Q-biotype B. tabaci on cotton to buprofezin is the highest(3.99-fold), The level of resistance of that to abamectin is the lowest(1.39-fold).