Biotech Updates

CryF1 Proteins Has No Effects on Cotesia marginiventris

April 30, 2014

The fall armyworm (Spodoptera frugiperda) is an important pest of maize in the United States and many tropical areas in the western hemisphere. Herculex I maize with the Cry1F gene was planted to control Lepidopteran pests, including S. frugiperda. A population of fall armyworm (Spodoptera frugiperda) discovered in Puerto Rico in 2006 had evolved resistance to Cry1F maize in the field, the first documented case of an insect with field resistance to a Bt plant. This resistant population was utilized in tri-trophic studies conducted with Cotesia marginiventris, a larval endoparisitoid of the fall armyworm.

The Cry1F-resistant S. frugiperda were studied to evaluate effects of Cry1F on Cotesia marginiventris over five generations. Possible prey-mediated effects were overcome and concerns about potential differences in laboratory or field-derived Bt resistance were avoided. Results clearly demonstrate that Cry1F maize does not affect development, parasitism, survivorship, sex ratio, longevity or fecundity of C. marginiventris when they parasitize Cry1F maize-fed S. frugiperda. Moreover, the level of Cry1F protein in the leaves was strongly diluted when transferred from Bt maize to S. frugiperda and was not detected in larvae, cocoons or adults of C. marginiventris. These results refute previous reports of C. marginiventris being harmed by Bt proteins.

Read More: