Development and reproduction of Tetranychus cinnabarinus (Acari: Tetranychidae) on transgenic insect-resistant cotton cultivars

Effects of transgenic insect-resistant Bt cotton Zhongkangza 5 and Lumianyan 23 and Bt + CpTI cotton sGK958 and Zhongmiansuo 45 on Tetranychus cinnabarinus growth and reproduction were compared with those of nontransgenic cotton (K836) under laboratory conditions. Developmental times of different T. cinnabarinus stages fed on transgenic Bt and Bt + CpTI cotton differed significantly from those fed on K836. Pre-oviposition (1.44 d) and oviposition (12.71 d) periods and female life span (14.11 d) were longer on K836 than on transgenic cotton. Maximum fecundity was 75.61 eggs per female on K836, while minimum fecundity was 54.68 eggs per female on sGK958. Net reproductive rate was highest with 55.00 female offspring on K836, whereas the lowest was 37.219 female offspring on Zhongkangza 5. The highest intrinsic rate of increase was 0.454 day 1 on K836, whereas the lowest was 0.246 day 1 on Zhongkangza 5. The highest finite rate of increase was 1.575 day 1 on K836, whereas the lowest was 1.278 day 1 on Zhongkangza 5. The shortest population doubling time was 1.526 d on K836, while the longest was 2.823 d on Zhongkangza 5. Thus, transgenic cotton inhibited T. cinnabarinus development and reproduction, indicating transgenic cotton could prevent damage by T. cinnabarinus or other pests.