转Cry1Ac+CpTI基因棉对棉田害虫及其天敌种群动态的影响

002年在河北省南皮县对转Cry1Ac+CpTI基因棉（SGK321）棉田害虫及其天敌种群动态的研究结果表明，SGK321棉田及其亲本对照棉（石远321）棉田的害虫和捕食性天敌的种类基本相同，但数量差异较大。但在5月23日至9月16日的24次调查中，SGK321棉田的5 种主要害虫棉铃虫、棉蚜、绿盲蝽、棉粉虱、小绿叶蝉的总数量分别较其亲本石远321棉田降低89.5%、64.5%、21.8%、15.6%和33.7%。SGK321棉田龟纹瓢虫和中华草蛉的种群总数量分别比石远321棉田增高34.0%和9.1%，但异色瓢虫、小花蝽、异须盲蝽、蚜茧蜂和蜘蛛类的种群数量分别降低28.6%、6.5%、43.1%、44.7%和14.0%。主要害虫和天敌种群动态的监测表明，棉蚜、小绿叶蝉和棉粉虱的发生高峰期分别为7月中下旬，8月下旬至9月中旬，8月下旬至9月上、中旬。在三者的高峰期内，SGK321棉田的种群数量基本上低于对照田。龟纹瓢虫的发生高峰期为7月上旬到8月上、中旬，且SGK321棉田的种群数量高于对照田。研究表明， SGK321在对棉铃虫具有很好抗性的同时，对棉蚜、棉粉虱、绿盲蝽、小绿叶蝉等非靶标害虫的发生也有一定的抑制作用；SGK321棉田龟纹瓢虫和中华草蛉的种群数量增加，其他主要天敌的数量则有所降低，表明SGK321对某些天敌种类的种群动态存在不利影响。

Effect of transgenic Cry1Ac + CpTI cotton (SGK321) on population dynamics of pests and their natural enemies

Effects of transgenic cotton (cv. SGK321, with inserted genes of Cry1Ac and CpTI) on population dynamics of pests and natural enemies were studied in Nanpi County, Hebei Province in 2002. It showed that the composition of pest and predatory species was similar between the plots of transgenic cotton SGK321 and its parental line, sy321 cotton, but with different accumulated numbers for each species. From 24 surveys during May 23-September 16, the accumulated number of the main pest species decreased in SGK321, compared to those of sy321, by 89.5%, 64.5%, 21.8%, 15.6% and 33.7% for Helicoverpa armigera, Aphis gossypii, Lygus lucorum, Bemisia tabaci and Empoasca flavescens, respectively. For the main natural enemies, the accumulated numbers of Propylaea japonica and Chrysopa sinica increased by 34.0% and 9.1%, respectively during the same period; but those of Harmonia axyridis, Orius minutus, Campylomma diversicornis, Lysiphlebia japonica and spiders decreased by 28.6%, 6.5%, 43.1%, 44.7% and 14.0%, respectively. Population dynamics of the main pest and predatory species showed that the population peak of A. gossypii, E. flavescens and B. tabaci occurred from the middle to late July, late August to mid_September, and late August to early and mid_September, respectively. And the individual number of each pest species was lower in SGK321 plot than in sy321 during its peak period. The population peak of P. japonica lasted from the early July to middle and late August, and its number is higher in SGK321 plot than in sy321 during this period. The results suggested that the transgenic cotton SGK321 had control efficiency not only to the cotton bollworm, but also to some non_target pests, such as the cotton aphid and the tobacco whitefly. The individual numbers of P. japonica and C. sinica increased in SGK321 plot, compared to those in sy321, but those of other main natural enemy species decreased, indicating some negative effects of the transgenic cotton SGK321 on natural enemy populations.