1 Scientific RepoRts | 6:28059 | DOI: 10.1038/srep28059 www.nature.com/scientificreports performance and cross-crop resistance of Cry1F-maize selected Spodoptera frugiperda on transgenic Bt cotton: implications for resistance management Fei Yang 1,2 , David L. Kerns 1,2 , sebe Brown 1 , Ryan Kurtz 3 , tim Dennehy 4 , Bo Braxton 5 , Graham Head 6 & Fangneng Huang 2 transgenic crops producing Bacillus thuringiensis (Bt) proteins have become a primary tool in pest management. Due to the intensive use of Bt crops, resistance of the fall armyworm, Spodoptera frugiperda, to Cry1F maize has occurred in Puerto Rico, Brazil, and some areas of the southeastern U.S. The sustainability of Bt crops faces a great challenge because the Cry1F-maize resistant S. frugiperda may also infest other Bt crops in multiple cropping ecosystems. Here we examined the survival and plant injury of a S. frugiperda population selected with Cry1F maize on three single-gene and fve pyramided Bt cotton products. Larvae of Cry1F-susceptible (SS), -heterozygous (RS), and -resistant (RR) genotypes of S. frugiperda were all susceptible to the pyramided cotton containing Cry1Ac/Cry2Ab, Cry1Ac/Cry1F/Vip3A, Cry1Ab/Cry2Ae, or Cry1Ab/Cry2Ae/Vip3A, and the single-gene Cry2Ae cotton. Pyramided cotton containing Cry1Ac/Cry1F was efective against SS and RS, but not for RR. These fndings show that the Cry1F-maize selected S. frugiperda can cause cross-crop resistance to other Bt crops expressing similar insecticidal proteins. Resistance management and pest management programs that utilize diversify mortality factors must be implemented to ensure the sustainability of Bt crops. This is especially important in areas where resistance to single-gene Bt crops is already widespread. Since 1996, transgenic crops expressing Bacillus thuringiensis (Bt) proteins have been widely planted in many countries 1 . Currently, maize, cotton and soybean are the three major commercial Bt crops. In 2014 alone, a total of >77 million hectares of Bt crops were planted worldwide, consisting of 62.4% maize, 31.1% cotton and 6.5% soybean 1 . Tese Bt crops are efective in controlling their target insect pests while causing little or no harm to non-target organisms 2,3 . Bt crops have ofered great benefts including reduced chemical insecticide use and crop yield loss 2–7 . However, the extensive use of Bt crops has placed a strong selection pressure on target pest popu- lations, with the potential consequence of rapid evolution of resistance, threatening these benefts 8–10 . In recent years, feld-evolved resistance to Bt crops that resulted in control problems has occurred in some target pests 11–16 . Te fall armyworm, Spodoptera frugiperda, is a well-known long-distance migratory insect native to the tropical regions of the Western Hemisphere from the U.S. to Argentina 17 . Field resistance to Cry1F maize in S. frugiperda, due to the intensive use of Bt crops, has been documented in Puerto Rico 11 , Brazil 15 , and the U.S. mainland 16 . To date, S. frugiperda is the frst and only target pest to develop feld resistance to Bt crops, at multiple locations, across diferent countries and continents. Currently, all the three major Bt crops are planted in Brazil throughout the year 18 , while in the southern U.S., Bt maize and Bt cotton are planted in close proximity to one another 16 . Cry1F protein is expressed in many varieties of these Bt maize and Bt cotton currently planted in the 1 Macon Ridge Research Station, Louisiana State University Agricultural Center, Winnsboro, LA 71295, USA. 2 Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA. 3 cotton Incorporated, 6399 Weston Parkway, Cary, NC 27513, USA. 4 Bayer CropScience, Research Triangle Park, NC 27709, USA. 5 Dow AgroSciences, Travelers Rest, SC, 29690, USA. 6 Monsanto Company, St. Louis, MO 63167, USA. Correspondence and requests for materials should be addressed to F.Y. (email: FYang@agcenter.lsu.edu) or D.L.K. (email: DKerns@agcenter.lsu.edu) received: 08 March 2016 accepted: 31 May 2016 Published: 15 June 2016 opeN