Impact of Bt-engineered cotton on target and non-target arthropods, toxin flow through different trophic levels and seedcotton yield uri icon

abstract

  • Insect-resistant genetically engineered cottons expressing ?-endotoxins from the bacterium, Bacillus thuringiensis (Bt) have been adopted on a large scale worldwide. The effects of Bt cotton on non-target insect pests, generalist predators, arthropod diversity and toxin flow through different trophic levels under insecticide protected and unprotected conditions was studied. The populations of major non-target insect pests (leafhoppers, whiteflies, ash weevils, aphids, dusky and red cotton bug, and green bug) and the generalist predators (ladybirds, chrysopids, and spiders) did not differ significantly between the Bt and non-Bt cottons, while their numbers were lower in insecticide protected than under unprotected conditions, except for aphids and whiteflies. Although, Bt toxin was detected in some insect species, no significant differences were observed in their abundance on Bt and non-Bt cottons. Species richness and diversity of plant inhabiting and soil dwelling arthropods was similar in Bttransgenic and non-transgenic cottons, except in a few cases. The Bt-transgenic cotton was effective for the management of bollworms, without any major adverse effects on the non-target arthropods

publication date

  • 2009