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以我国培育的转Bt基因棉花（简称Bt棉）为材料，系统测定了Bt棉叶片对棉铃虫Helicoverpaarmigera（Hubner）不同龄期幼虫的杀虫活性和抑制生长的作用。结果表明，Bt棉的杀虫活性随着龄期的增大而趋于降低，其中处理3d只对1龄幼虫有较高效果；从1～4龄开始连续取食Bt棉后均不能化蛹，5龄幼虫则能正常化蛹。3龄幼虫取食Bt棉叶3d后的体重与初始体重之比为0．94，而取食常规棉叶的相应比值为5．48，对幼虫生长的抑制作用明显。在28℃条件下用Bt棉饲养棉铃虫1～3龄幼虫3d，对幼虫的致死率显著高于25℃处理，对3龄幼虫抑制生长的作用也显著提高。研究结果可为确定棉铃虫对Bt棉的抗性监测与治理技术以及Bt棉的田间应用技术提供依据。
The transgenic Bt cotton cultivated in China (Bt cotton) was used to systematically determine the insecticidal activity and growth inhibitory effect of Bt cotton leaves on different instar larvae of Helicoverpa armigera (Hubner). The results showed that the insecticidal activity of Bt cotton tended to decrease with the increase of the age, of which the treatment of 3d only had a higher effect on the first instar larvae; the pupae could not be pupated after continuous feeding of Bt cotton from the first to the fourth instar. , 5th instar larvae can normalize pupae. The ratio of body weight to initial body weight of 3rd instar larvae feeding on Bt cotton leaf for 3 days was 0.94, while the corresponding ratio of feeding conventional cotton leaf was 5.48, which significantly inhibited the growth of larvae. At 28 ℃, Bt cotton was used to feed 3d instar larvae of 1st and 3rd instar larvae of Helicoverpa armigera, the lethality to larvae was significantly higher than that of 25 ℃, and the inhibitory effect on 3rd instar larvae was also significantly increased. The results provide the basis for the determination of cotton bollworm resistance to Bt cotton monitoring and management techniques and field application of Bt cotton technology.