Geographical susceptibility of corn earworm populations in the southeastern United States to Bacillus thuringiensis Cry1Ab and Vip3A proteins

On-Demand

Presenting Author(s)

Ying Niu

Louisiana State University Agricultural Center
Baton Rouge, Louisiana

Co-Author(s)

Oi

Oyediran O. isaac

Syngenta Crop Protection LLC
Research Triangle Park, North Carolina
Wenbo Yu

Louisiana State University
Baton Rouge, Louisiana
Shucong Lin

Louisiana State University AgCenter
Banton Rouge, Louisiana
MD

Marcelo Dimase

University of Alberta
Baton Rouge, Louisiana
SB

Sebe Brown

University of Tennessee
Jackson, Tennessee
FR

Francis P.F. Reay-Jones

Clemson University
Florence, South Carolina
DC

Donald Cook

Mississippi State University
Stoneville, Mississippi
DR

Dominic Reisig

North Carolina State University
Plymouth, North Carolina
BT

Benjamin Thrash

University of Arkansas
Lonoke, Arkansas

The corn earworm, Helicoverpa zea (Boddie), is a target species of pyramided Bt corn and cotton in the United States. Cry1Ab is one of the first-generation Bt proteins expressed in commercialized Bt crops, while Vip3A is a relatively new protein expressed in many pyramided Bt crops. During 2018 and 2019, a total of 32 H. zea populations were collected from Bt and non-Bt crops in seven southeastern states of the U.S. Compared to a known susceptible laboratory strain of H. zea, diet-overlay bioassays showed that the field populations were 2- to >150-fold resistant to Cry1Ab, while all the field populations tested ere susceptible to Vip3A with LC₅₀ values ranging from > 11-fold more sensitive to 9-fold more tolerant to the protein. There was a positive linear relationship in the susceptibilities of the field populations to Cry1Ab and Vip3A. Data generated from this study should provide useful information in Bt resistance monitoring and proper use of gene pyramiding for management of H. zea.