Genetically Modified Corn and Effects on Nearby Crops
The use of genetically modified corn seeds has been the subject of much debate, as questions persist over cost-effectiveness, yield, long-term effectiveness and the impact on non-GE plants. The controversy runs deep enough that some countries continue to ban genetically modified crops, yet they make up the majority of corn, soybeans and cotton grown in the United States.
A 2010 study published in the journal Science, “Areawide Suppression of European Corn Borer with Bt Maize Reaps Savings to Non-Bt Maize Growers,” explores the impact of genetically modified crops on the health of neighboring crops in U.S. agriculture. The researchers tested the impacts specifically from corn genetically modified to make insecticidal proteins derived from bacterium Bacillus thuringiensis (Bt), referred to as Bt corn.
The study’s findings include:
- The damages from European corn borers decreased significantly in both Bt corn and the non-Bt corn that was planted nearby. This “halo-effect” was attributed to the way female corn borers lay eggs indiscriminately on Bt or non-Bt crops.
- Though Bt corn seed is more expensive, planting a mix of Bt corn and non-Bt corn yielded enough of a benefit that it outweighed the increased seed costs.
- Mixing Bt corn with non-Bt corn should increase the length of time it takes for corn borers to develop a resistance to the pesticide.
- Over a 14-year period, Illinois, Minnesota and Wisconsin have seen an estimated $3.2 billion benefit for corn growers; $2.4 billion of that has accrued to non-Bt corn growers. Iowa and Nebraska saw an estimated $3.6 billion in benefits, with $1.9 billion for non-Bt corn growers.
The study has implications for farms throughout the developing world, the researchers say, where yields, cost-effectiveness and sparse arable land are pressing concerns. Previous studies have concluded that pest-resistant corn helps neighboring non-genetically modified crops, but it was believed that the increased cost of the genetically modified seed would outweigh the financial benefits in overall crop yield.
Note to instructor: The suggested assignments are designed for flexibility. They can be used in whole or part and can be adapted to a particular task -- for example, the newswriting assignments could be applied to the writing of the headline, the lead, the nut graph or the full story. Material from the assignments could also be combined with other material, for example, in the writing of a background, feature or local-angle story.
- Summarize the study in fewer than 40 words.
- Express the study's key term(s) in language a lay audience can understand.
- Evaluate the study's limitations. (For example: Do the results conflict with those of other reliable studies? Are there weaknesses in the study's data or research design?)
Read the study-related Reuters article titled "Genetically modified corn helps nearby fields: study."
- Reporter's use of the study: Evaluate what the reporter chose to include and exclude from the study. Would the audience have acquired a clear understanding of the study's findings and limits from this article?
- Reporter's use of other material: Assess the material in the article that is not derived from the study. (for example: Does the reporter place the study in the context of other research and to what effect? Does the reporter include reactions to the study from other researchers or interested parties [e.g., political groups business leaders, or community members] and are their credentials or possible biases made clear?)
- Write a lead (or headline or nut graph) based on the study.
- Spend 60 minutes exploring the issue by accessing sources of information other than the study. Write a lead (or headline or nut graph) based on the study but informed by the new information. Does the new information significantly change what one would write based on the study alone?
- Interview two sources with a stake in or knowledge of the issue. Be prepared to provide them with a short summary of the study in order to get their response to it. Write a 400-word article about the study incorporating material from the interviews.
- Spend additional time exploring the issue and then write a 1,200-word background article, focusing on major aspects of the issue.