As Midwest Landscape Changes, Insecticide Use Increases
The Midwest United States of America is home to some of the most fertile soil in the world. Its mild climate and ample rainfall make it the agricultural heart of America. Over the years, cropland has expanded so much that natural ecosystems are becoming rarer. The continued retreat of natural habitat and growth of farms have greatly simplified the landscape. From the air, this section of the country looks like a never-ending grid. A new study from the Great Lakes Bioenergy Research Center (GLBRC) concluded that the simplification of the landscape has led to an increased abundance of crop pests and therefore higher use of insecticides.
The correlation between decreasing natural habitat and higher insecticide use is not a new idea. But it has never been supported with empirical evidence until this study. The study found that counties with less habitat had greater rates of insecticide use. In fact, the study that the overall simplification of the agricultural landscape resulted in the application of insecticide to an additional 5,400 square miles, an area the size of Connecticut.
"When you replace natural habitat with cropland, you tend to get more crop pest problems," says lead author Tim Meehan, University of Wisconsin—Madison associate scientist in the Department of Entomology. "Two things drive this pattern. As you remove natural habitats you remove habitat for beneficial predatory insects, and when you create more cropland you make a bigger target for pests — giving them what they need to survive and multiply."
The study did offer solutions to this problem in the Midwest: the planting of perennial bioenergy crops like switchgrass and mixed prairie. These plants do not require insecticides and can provide a home to predatory species that consume the crop-destroying pests.
"Perennial crops provide year—round habitat for beneficial insects, birds, and other wildlife, and are critical for buffering streams and rivers from soil erosion and preventing nutrient and pesticide pollution," says Doug Landis, Michigan State University professor of entomology and landscape ecology.
They can also be harvested for the production of ethanol, making them profitable to farm owners and not just wasted land. The GLBRC has made their case in this report for a new environmental policy. Stop the simplification of the Midwestern landscape. Diversify agricultural areas. Decrease the need for insecticides. Harvest a perennial bioenergy crop that grows naturally and provides habitat for wildlife.
According to University of Wisconsin-Madison professor of entomology, Claudio Gratton, "We are at a junction right now. There is increased demand for renewable energy, and one big question is: where it will come from? We hope that these kinds of studies will help us forecast the impacts that bioenergy crops may have on agricultural landscapes."
The study has been published in the Proceedings of the National Academy of Sciences.
Link to published article: http://www.pnas.org/content/108/28/11500.abstract?sid=f7137751-5a70-4773-b905-bf05479fb5c6
Image credit: http://www.news.wisc.edu/19554