Skip to main content
ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Publications at this Location » Publication #300270
Title: Susceptibility to Bt proteins not required for Agrotis ipsilon aversion to Bt maize

Author
item BINNING, RACHEL - Dupont Pioneer Hi-Bred
item COATS, JOEL - Iowa State University
item XIAOXIAO, KONG - Dupont Pioneer Hi-Bred
item Hellmich Ii, Richard

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/2/2014
Publication Date: 10/10/2014
Citation: Binning, R., Coats, J., Xiaoxiao, K., Hellmich II, R.L. 2014. Susceptibility to Bt proteins not required for Agrotis ipsilon aversion to Bt maize. Pest Management Science. 71(4):601-606.

Interpretive Summary: Genetically modified maize with resistance to insects, known as Bacillus thuringiensis (Bt) maize, is popular to growers in the U.S. and is very effective against the European corn borer, Ostrinia nubilalis. But there are questions about the susceptibility and behavioral response of other insect pests to Bt maize in countries where this maize is not currently cultivated. These are important factors to consider as management plans are developed. These factors were investigated for the black cutworm, Agrotis ipsilon, a global pest of maize. Black cutworm larvae demonstrated a pre-ingestive aversion to Cry1F Bt maize, but development and mortality were still affected. Survival on Cry1F maize tissue was 40% and weight gain of survivors of Cry1F tissue exposure was significantly reduced. A similar aversion was seen for Cry34Ab1/Cry35Ab1 maize; however longer-term feeding, weight gain, and survival were not affected. Black cutworm larvae showed aversions to both Bt treatments. Aversion to Cry34Ab1/Cry35Ab1 maize was unexpected because these proteins have no known toxic effect against Lepidoptera, however results confirm that this aversion was temporary and did not affect growth or development. The Cry1F results suggest black cutworm larvae will abandon Cry1F maize in the field before any selection for resistance. These data support the use of refuge to delay Cry1F resistance development in black cutworm populations. This information is useful to all scientists interested in developing insect resistance management plans to safeguard the Bt maize technology and will be useful to Bt maize growers worldwide.

Technical Abstract: Although Bacillus thuringiensis (Bt) maize has been widely adopted in diverse regions around the world, relatively little is known about the susceptibility and behavioral response of certain insect pests to Bt maize in countries where this maize is not currently cultivated. These are important factors to consider as management plans are developed. These factors were investigated for the black cutworm, Agrotis ipsilon, a global pest of maize. Agrotis ipsilon demonstrated an initial, pre-ingestive aversive response to Cry1F maize. Development and mortality also were affected – survival on Cry1F maize tissue was 40% and weight gain of survivors of Cry1F exposure was significantly reduced. A pre-ingestive aversive response LSO was seen for Cry34Ab1Cry35Ab1 maize; however longer-term feeding, weight gain, and survival were not affected. Agrotis ipsilon showed aversion to both Bt treatments. Aversion to Cry34Ab1/Cry35Ab1 maize was unexpected because these proteins have no known toxic effect against Lepidoptera, however results confirm that this aversion was temporary and did not affect growth or development. The Cry1F results suggest A. ipsilon will abandon Cry1F maize in the field before any selection for resistance. These data support the use of refuge to delay Cry1F resistance development in A. ipsilon populations.