This article list the types of Bt present in all commercialized corn in the U.S.A. in a concise format. It presents the trade names for traits, Bt event, protein(s) expressed, targeted insects and herbicide traits.

Now in its 22nd year, the Trait Table for field corn has become the standard as an authoritative reference to Bt toxins in corn. Dr. Chris DiFonzo at Michigan State University is the author, and questions or comments should be directed to her (Chris DiFonzo — or 517-353-5328).  

Note about insect resistance to Bt corn

The Bt Trait Table has a column titled 'Species w/ resistance to all Bts in package' to highlight insect x Bt combinations with documented field-failures, confirmed resistance, or cross-resistance. These statements are based on published lab assays &/or field research as documented in the link above for "citations for resistance statements ...'. This column is intended to alert growers and consultants to potential management problems, influence seed selection, and encourage field scouting. It is important to note that the Trait Table is a national publication and resistance may be widespread (as in western bean cutworm) or regional (as in corn rootworm). Check with your local seed company or extension personnel for the types of Bt resistance present in your area.

Updated Design for 2024

In the past, all Bt trait packages have been in the trait table. But over the years, some industry colleagues commented that leaving older products in the table was confusing if growers assumed they could still be purchased. However, information on older packages is needed to interpret planting or research records from previous years. Also, companies still refer to original traits (like Herculex I or YieldGard) on field signs, web sites, and seed guides, because single traits are components of newer multi-trait hybrids.

To finally address this concern, the 2024 table is split. I looked at 2024 seed guides from the major seed companies plus many smaller regional providers. If I found a trait package offered in at least one hybrid, from any company, it stayed on the current trait table (page 2). Trait packages which were not found as standalone hybrids were moved into a new ‘phased out’ table (below) for historical reference. Hopefully, this split addresses any confusion in availability. This is a work in progress; if you see an error in the ‘phased out’ table, send me some evidence and I’ll move that package back into the current table.

New Bt names: Names of pesticidal proteins that come from bacteria were recently updated. Most Bts in the trait table are unchanged, but Cry34/35Ab1 is now Gpp34Ab1/Tpp35Ab1. I kept the old name in the Bt Trait Table for now, since many seed guides and extension materials haven’t caught up to the change. But related materials on the Texas A&M website are up to date.

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