›› 2003, Vol. 46 ›› Issue (6): 705-712.

• RESEARCH PAPERS • Previous Articles     Next Articles

Effects of transgenic Bt cotton and transgenic Bt+CpTI cotton on populat ion dynamics of main cotton pests and their natural enemies

SUN Chang-Gui, ZHANG Qing-Wen*, XU Jing, WANG Yin-Xia, LIU Jun-Li   

  • Online:2003-12-20 Published:2003-12-20
  • Contact: ZHANG QingWen

Abstract: Systematic studies were carried out on effects of univalent transgenic cotton(GK321) containing the gene CryIAc and bivalent transgenic cotton (SGK321) carrying the genes CryIAc+CpTI on population dynamics of the main pests and their enemies in experimental fields of Chinese Academy of Agricultural Sciences (Xibeiwang, Beijing) from April to October in 2002 This experiment included three treatments. The first was a univalent transgenic cotton plot (UTCP), the second a bivalent transgenic cotton plot (BTCP), and the third a routine cotton plot (RCP). The results indicated that both univalent and bivalent transgenic cottons were excellently resistant to the cotton bollworm, Helicoverpa armigera. There was no significant difference in resistance between bivalent and univalent transgenic cottons in the second generation of cotton bollworm; but the resistance of bivalent cotton was significantly higher than that of univalent cotton in the third generation: number of larvae in bivalent cotton plot decreased by 36.6% compared with univalent cotton plot. The populations of nontarget pests in transgenic plots were significantly higher than those in normal cotton plot; with regard to individual pest species, number in bivalent and univalent transgenic plots was different. Compared with univalent cotton plot, Aphis gossypii Glover, Empoaca biguttula Shiraki and Bemisia tabaci Gennadius in bivalent transgenic cotton plot decreased in individual number respectively by 33.0% (P<0.01), 50.6% (P<0.01) and 22.7% (P>005), but Thrips tabaci Lindeman and Lygus lucorum MeyerDür increased respectively by 208.9% (P<0.01) and 18.4% (P>0.05). The population sizes of majority of natural enemies (including predatory and parasitic enemies) investigated were significantly lower in transgenic otton plots than in normal cotton plot. Compared with univalent cotton plot, Propylaea japonica(Thunberg), Lysiphlebia japonicus Ashmead and Allothrombium ovatum in bivalent transgenic cotton plot decreased in individual number significantly by 30.4%, 42.8% and 46.8% respectively. Eggs of Chrysopa sinica Tjeder and Araneida decreased respectively by 20.0% and 27.4% with no significance; Chrysopa sinica Tjeder and Orius minutus Linnaeus increased respectively by 27.0% significantly and 8.9% with no significance.

Key words: Univalent transgenic cotton, bivalent transgenic cotton, pests, natural enemies, population dynamics