MICHIGAN STATE (US) — Having a single, dominant crop rather than a variety of wild plants has resulted in more pests and insecticide use. Planting perennial bioenergy crops may offset the negative effects.
Perennial crops like switchgrass and mixed prairie “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, entomologist and landscape ecologist at Michigan State University.
Because landscape simplification has long been assumed to increase pest problems, counties with less natural habitat have higher rates of insecticide use.
A new study, published in the journal Proceedings of the National Academy of Sciences finds, for example, that it was associated with annual insecticide application to an additional 5,400 square miles in the Midwest—an area the size of Connecticut.
“When you replace natural habitat with cropland, you tend to get more crop pest problems,” says Tim Meehan, an entomologist at the University of Wisconsin.
“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.”
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