Cry1F resistance in fall armyworm Spodoptera frugiperda: single gene versus pyramided Bt maize.
Evolution of insect resistance to transgenic crops containing Bacillus thuringiensis (Bt) genes is a serious threat to the sustainability of this technology. However, field resistance related to the reduced efficacy of Bt maize has not been documented in any lepidopteran pest in the mainland U.S. after 18 years of intensive Bt maize planting. Here we report compelling evidence of field resistance in the fall armyworm, Spodoptera frugiperda (J.E. Smith), to Cry1F maize (TC 3507) in the southeastern region of the U.S. An F2 screen showed a surprisingly high (0.293) Cry1F resistance allele frequency in a population collected in 2011 from non-Bt maize in south Florida. Field populations from non-Bt maize in 2012-2013 exhibited 18.8-fold to >85.4-fold resistance to purified Cry1F protein and those collected from unexpectedly damaged Bt maize plants at several locations in Florida and North Carolina had >85.4-fold resistance. In addition, reduced efficacy and control failure of Cry1F maize against natural populations of S. frugiperda were documented in field trials using Cry1F-based and pyramided Bt maize products in south Florida. The Cry1F-resistant S. frugiperda also showed a low level of cross-resistance to Cry1A.105 and related maize products, but not to Cry2Ab2 or Vip3A. The occurrence of Cry1F resistance in the U.S. mainland populations of S. frugiperda likely represents migration of insects from Puerto Rico, indicating the great challenges faced in achieving effective resistance management for long-distance migratory pests like S. frugiperda.
Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, United States of America.
Fangneng
F
Huang
Department of Entomology and Nematology, University of Florida, Institute of Food and Agricultural Sciences, Southwest Florida Research and Education Center, Immokalee, Florida, United States of America.
Jawwad A
JA
Qureshi
Insect Behavior and Biocontrol Unit, USDA-ARS CMAVE, Gainesville, Florida, United States of America.
Robert L
RL
Meagher
Department of Entomology, North Carolina State University, Vernon G. James Research and Extension Center, Plymouth, North Carolina, United States of America.
Dominic D
DD
Reisig
Monsanto Company, St. Louis, Missouri, United States of America.
Graham P
GP
Head
Department of Entomology, University of Minnesota, St. Paul, Minnesota, United States of America.
David A
DA
Andow
USDA, Agricultural Research Service, Crop Genetics and Breeding Research Unit, Tifton, Georgia, United States of America.
Xinzi
X
Ni
Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, United States of America.
David
D
Kerns
UGA-Griffin Campus, Department of Entomology, the University of Georgia, Griffin, Georgia, United States of America.
G David
GD
Buntin
Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, United States of America.
Ying
Y
Niu
Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, United States of America.
Fei
F
Yang
Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, United States of America.
Vikash
V
Dangal
D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics*; D001427:Bacterial Toxins / Q000235:genetics*; D060467:Disease Resistance; D007300:Insect Control / Q000379:methods; D030821:Plants, Genetically Modified; D018411:Spodoptera / Q000382:microbiology*; D003313:Zea mays / Q000235:genetics* / Q000469:parasitology*
D001427:Bacterial Toxins