College of Agriculture & Natural Resources
AGNR Research

Forty Years of Data Quantifies Benefits of Bt Corn Adoption Across a Wide Variety of Crops for the First Time

Myriad benefits include 90% suppression of pests, severely limited spraying and multiple millions in economic benefits
Photo Credit: 
Edwin Remsberg

UMD researchers have pulled together forty years of data to quantify the effects of Bt corn, a highly marketed and successful genetically modified corn variety, in a novel and large-scale study. Other studies have demonstrated the benefits of Bt corn adoption on pest management for pests like the corn borer in corn itself for years, but this is the first study to look at the effects on other offsite crops in North America. By gaining control of the corn borer population, this study shows significant decreases in recommended spraying regimens, pest populations, and overall crop damage not just for corn, but for peppers, green beans, and other important crops to North American agriculture. These benefits have never before been documented and showcase Bt corn as a powerful tool to combat pesticide resistance and advance the agricultural industry.

Bt corn was first introduced and adopted in the United States in 1996 and is a genetically modified organism or GMO that makes up over 90% of our current corn population. In this study, Dr. Galen Dively, Professor Emeritus and Integrated Pest Management Consultant in the Department of Entomology, and Dr. Dilip Venugopal, UMD Research Associate, use data from 1976 - 2016 to look at trends twenty years before and twenty years after adoption of Bt corn. “Safety of Bt corn and other GMOs has been tested and proven extensively, but this study is about effectiveness of Bt corn as a pest management strategy, particularly for offsite crops or different crops in different areas than the Bt corn itself,” explains Venugopal.

“This is the first paper published in North America showing offsite benefits to other host plants for a pest like the corn borer, which is a significant pest for many other crops like green beans and peppers,” says Dively. “We are seeing really more than 90% suppression of the corn borer population in our area for any crop, which is incredible.”

Using numbers from pest traps to estimate the population and examine the recommended spraying regimens for pests like the corn borer, Dively and Venugopal observed significant reductions in the population, with much less spraying occurring over time. “There would be no recommendation to spray for the corn borer given the current population, and this paper can trace that back to Bt corn adoption,” explains Dively. “What’s more, by looking at the actual pest infestations and damage on actual crops over forty years of data, we took it a step farther to see the benefits on all sorts of crops and the declines in the actual pest population. We are able to see the results in theory and in practice on actual crops and in the real pest population over a long stretch of time.”

“The next steps would to be quantify the millions and millions of dollars in economic benefits we see here in a very concrete way to show money and time saved on spraying and pest management, crop damage reduction, as well as consideration of the environmental benefits. The important thing here, however, is to think of Bt corn as one of many tools in an integrated pest management tool box. The benefits are undeniable, but must always be weighed against many other options to use a broad range of tools and maximize benefit while minimizing any potential risks,” explains Venugopal.

Dively concludes, “This study ultimately shows the importance of evaluating GMO crops beyond the field that is being planted. These products and the new advances coming down the pike have the potential to suppress major pest populations just like Bt corn has. This is just the beginning, and we need to be quantifying these effects. I am excited by these results and encouraged for future work.”

Their paper is published in the Proceedings of National Academy of Sciences and can be found here">http://www.pnas.org/content/early/2018/03/06/1720692115">here.

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