Submitted to: Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/9/2010
Publication Date: 10/8/2010
Publication URL: www.sciencemag.org
Citation: Hutchison, W.D., Burkness, E.C., Mitchell, P.D., Moon, R.D., Leslie, T.W., Fleischer, S.J., Abrahamson, M., Hamilton, K.L., Steffey, K.L., Gray, M.E., Hellmich II, R.L., Kaster, V., Hunt, T.E., Wright, R.J., Pecinovsky, K.T., Rabaey, T.L., Flood, B.R., Raun, E.S. 2010. Areawide suppression of European corn borer with Bt maize reaps savings to non-Bt maize growers. Science. 330:222-225. Interpretive Summary: In the U.S., maize has been the most abundant transgenic crop planted to resist insect pests, with hybrids engineered to express insecticidal proteins isolated from the bacterium Bacillus thuringiensis (i.e., Bt maize). Historically, the most damaging insect pest throughout the U.S. Corn Belt has been the European corn borer. The pest was accidently introduced in the eastern U.S. in 1917 and subsequently spread with devastating results; losses were previously estimated at $1 billion per year. In spite of its polyphagous nature, that could have mitigated regional population declines, we show that the planting of Bt maize has contributed to a significant cumulative suppression of larval and moth populations in five major maize producing states. We also show that the suppression effect provides significant economic gains to growers that plant non-Bt maize as well as those planting Bt maize. Although recent studies have shown regional suppression effects of Bt cotton on two pest species, this analysis is the first to demonstrate that areawide pest suppression is directly associated with cumulative Bt crop use, and that positive economic returns to growers of non-Bt crops also should be considered when assessing the benefits and costs of transgenic crop technologies. This information is useful for all stakeholders, particularly growers, interested in identifying benefits associated with Bt crops.
Technical Abstract: Transgenic maize, engineered to express insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) has become one of the most widely adopted pest management technologies in U.S. agriculture. In 2009, Bt maize was planted on more than 22.2 million ha, comprising 63% of the U.S. crop. The technology, to date, has primarily been targeted at one of the most damaging maize pests, the European corn borer (Ostrinia nubilalis). We use long-term time series of O. nubilalis larval infestations and moth flights to assess evidence for pest population suppression in five major maize producing states. We show that suppression is directly associated with cumulative Bt maize use over time, resulting in reduced per capita population growth rates. Previous economic assessments of Bt crops focused solely on benefits to the Bt crop area. We also find significant economic benefits for farmers planting non-Bt maize. Cumulative benefits to Bt and non-Bt maize during 13 growing seasons are conservatively estimated at more than $6.1 billion for a 5-state region, with cumulative benefits to non-Bt maize accounting for almost $3.9 billion of this total. These results affirm theoretical predictions of pest population suppression, and producer incentives to maintain sizeable non-Bt maize refugia for sustainable resistance management.