Studies On The Efeects Of Transgenic Bt Cotton On The Non-Target Organisms And Secondary Pests Of Cotton Field

Transgenic Bt cotton has been widely extended 1,500,000 ha every year in our country, the effects on non-target organisms and minor pests are one of the most important contents of its bio-safety assessment. In the present article, we used the high resistant cotton bollworm strain to Bt cotton (YCR) for the first time, to assess the effects of resistant cotton bollworm fed with the leaves of Bt cotton on the growth and development of parasistic natural enemies Microplitis mediator and Campoletis chlorideae and predatory ones Harmonia axyridis and Chrysopa septempunctata, and investigated the parasitization of parasistic natural enemies in Wei County Hebei Province where Bt cotton has been planted lor 5 years on end ( the resistance alleles frequency of cotton bollworm to Bt cotton has been increasing significantly every year in this district, it has been up to 9% now), we also investigated the occurrence and harm of Adelphocors sutualis and other sucking-pests in the Bt cotton experimental fields of Funing, Changshu and Liuhe County and our campus, in order to offer scientific basis for bio-safety assessment of Bt cotton.After feeding the resistant cotton bollworm YCR neonates with the inverse 2nd leaves on the mam stems of 5 to 8 leaves seedling stage Bt cotton for 3d, it was found that the growth and development velocity of the above larvae significant slower than the susceptible larvae feeding on the common cotton(CK), the sequences are as follows: YCR neonates fed on Zhongshuangkang (Bt plus CpTI) (middle 1st instar larvae to later ones occupied 64.3%)< YCR neonates fed on Xinmian33B (Bt)(later T1 instar larvae to earlier 2nd instar occupied 71.2%) and YCR neonates fed on Shuangkang321 (Bt plus CpTI) (later 1st instar larvae to earlier 2nd instar occupied 77.6%) 60.9% and 68. 2%, and cocoon weight of Zhongshuangkang and Xinmian 33" treatments decreased by 20.9% and 17. 2%, respectively, and resistant cotton bollworm fed on the leaves of Sumian 12 also had significant effects on the rate of parasitization and cocoon weight of M. mediator, which decreased by 41. 5% and 47. 3%, respectively, when compared that with CK; parasitization rate of C. chlorideae of the three kinds of Bt cotton treatments decreased by 39.9%^ 49. 7% and 46. 6%, cocoon rate by 45. 2%% 50. 4% and 44. 2%, emergence rate by...