Lincoln, Nebraska, USA
October 18, 2010
Transgenic corn’s resistance to pests has benefited even non-transgenic corn, according to a new study of Nebraska, Minnesota, Iowa, Illinois, and Wisconsin data.
The study, published in the Oct. 8 edition of the journal Science, found that widespread planting of genetically modified Bt corn in the upper Midwest has suppressed the European corn borer in both transgenic and non-transgenic fields. This areawide suppression has dramatically reduced the estimated $1 billion in annual losses caused by the European corn borer, historically a primary corn pest.
Bt corn, introduced in 1996, provides a built-in defense against attacks by the larvae of European corn borers and other insect pests. Larvae that ingest the Bt protein soon stop feeding and die, typically within 48 hours. Because it is effective at controlling corn borers and other pests, Bt corn has been adopted on about 63% of all U.S. corn acres.
As a result of planting Bt hybrids, corn borer numbers have also declined in neighboring non-Bt fields by 28%-73% in Minnesota, Illinois, and Wisconsin. Similar declines were documented in Nebraska and Iowa.
The researchers estimate that farmers in Nebraska, Iowa, Illinois, Minnesota, and Wisconsin received cumulative economic benefits of nearly $7 billion between 1996-2009, with benefits of more than $4 billion for non-Bt corn farmers alone.
UNL Extension Entomologists Robert J. Wright and Tom E. Hunt were coauthors of the Science article. They contributed data to this study from research conducted at the South Central Agricultural Lab at Clay Center and the Haskell Agricultural Lab at Concord. They documented the change in corn borer moth flights and infestations from before and after the introduction of Bt corn in 1996. Their data mirrored the findings from the other states on the areawide pest-control benefits from planting Bt corn.
Another Nebraska co-author was Earl S. Raun, former head of the UNL Department of Entomology, former associate director of UNL Extension, and for many years, a private crop consultant in Nebraska. Raun contributed to the research and analysis. He died July 6, 2009.
This study was co-authored by University of Minnesota entomology professor William Hutchison, chief author, and Paul Mitchell, an agricultural economist at the University of Wisconsin-Madison. Mitchell emphasized that "previous cost-benefit analyses focused directly on transgenic crop acres. This study is the first to include the value of areawide pest suppression and the subsequent benefits to growers of non-transgenic crops. In this case, the value of the indirect yield benefits for non-Bt corn acres exceeded the net value of direct benefits to the Bt corn acres."
Extended Benefits of Planting Bt Corn
Potato, green bean, and other host crops also stand to benefit from areawide reductions of corn borers, the researchers note, although this aspect was not part of this study.. The team's Science report also highlights the importance of the use of non-Bt refuges and other strategies to slow the corn borer's ability to develop resistance to Bt and thus maintain the insecticidal proteins' long-term effectiveness.
The Bt proteins provide the plant with a built-in defense against attacks by the larvae of European corn borers and other insect pests. In addition to reducing the use of insecticides that also can endanger beneficial insects, the Bt defense strategy helps prevent harmful molds from gaining entry to the plants via wound sites from borer feeding. Some of these molds, like Fusarium, produce mycotoxins that can diminish the value and safety of the crop's kernels.
The study authors emphasized that sustaining the economic and environmental benefits of Bt corn and other transgenic crops for adopters and non-adopters alike depends on the continued stewardship of these technologies.
Based on releases from the University of Minnesota and USDA’s Agricultural Research Service and information from Robert Wright and Tom Hunt, UNL, Co-authors of the Science article
Topics
Species
