Effect of Bt Maize on the Plant-Aphid–Parasitoid Relationships

Genetically modified Bt maize varieties are designed to control certain pests (Coleoptera and Lepidoptera) by expressing Cry proteins of Bacillus thringiensis. University of Lleida researcher Belén Lumbierres and colleagues studied the effect of Bt maize on aphid parasitism and measured the aphid-parasitoid complex in field conditions. They used three Bt maize varieties, two coming from Event MON810 and one from Bt 176; and genetically similar lines or near-isogenic lines (NIL). There was no difference in the aphid abundance in between Bt varieties and NIL. Differences within the Bt varieties and the NILS were observed only in one year of the two-year study. This may be due to the background of the variety or the environmental conditions in the two years of the study. The prevalent parasitoids observed were Lysiphlebus testaceipes (Cresson), Lipolexis gracilis Förster (Hymenoptera, Braconidae, Aphidiinae) and Aphelinus sp. (Hymenoptera, Aphelinidae). Bt maize had no effect on aphid-parasitoid association, aphid parasitism, and hyperparasitism (a condition in which a secondary parasite develops within a previously existing parasite). Therefore, the results imply that Bt maize has no negative effect on the relationships of the three different levels of the food chain studied.

Read the research article released by the BioControl Journal at http://www.springerlink.com/content/k263151255227715/.