Incidence of insect predators and parasitoids on transgenic Bt cotton in comparison to non-Bt cotton varieties

Transgenic bt (bacillus thuringiensis) cotton (gossypium hirsutum l.) genetically modified from and expressing delta-endotoxin protein has been increasingly preferred by pakistani farmers due to high production potential and targeted control of bollworms. a field study was conducted to evaluate the impact of bt cotton on insect predators and parasitoids population in comparison to conventional (non bt) cotton varieties. the available non-bt cotton varieties/line (aari-fh- 942,nibge-nn3,niab-112) and bt cotton varieties/line (aari-fh-114,nibge-ir-3701,4b-tarzan-1) were sown during 2012-13 cotton season. population of insect predators and parasitoids were observed from 1st week of july to 2nd week of november. the results revealed that the abundance of insect predators; chrysoperla carnea,coccinella septempunctata,geocoris spp.,menochilus sexmaculata,and parasitoids: trichogramma spp.,apanteles spp.,did not differ significantly on non- bt and transgenic bt varieties. their population almost equally distributed in both types of fields. the results conclude that transgenic bt cotton have no adverse impact on population dynamics and distribution of insect predators and parasitoids under field conditions. copyright 2015 zoological society of pakistan.