Syngenta genetically modified corn showing rootworm vulnerability

Indication of concern, but more study needed, say Syngenta researchers

Syngenta AG‘s genetically modified Agrisure corn may have “cross resistance” with Monsanto‘s YieldGard corn, making the crop vulnerable to the same rootworm no longer killed by Monsanto’s toxin, according to researchers.

Cross-resistance may already be showing up in Nebraska cornfields, said Lance Meinke, an entomology professor at the University of Nebraska in Lincoln. Research there showed that rootworms have a low resistance to Monsanto corn, and Syngenta corn had similarly poor performance.

“This has been the most difficult insect to control in the Corn Belt in my lifetime,” said Dirk Benson, Syngenta’s head of trait projects. “We are very concerned about trait performance.” In a recent study, rootworms known to be resistant to the incecticidal protein Cry3Bb1, similar to the mCry3a protein produced by Syngenta corn, survived feeding on Syngenta’s corn and caused root damage at higher-than-expected rates. But the study is preliminary and some of it doesn’t support the possibility of cross-resistance, said Benson. “They have an indication of concern,” said Benson. “More study is needed.”