In the U.S., the environmental and economic costs caused by invasive species are estimated to exceed $120 billion per year. Since invasive pests have few or no natural predators, they can quickly spread, and throw off entire ecosystems by pushing out native species and reducing biological diversity. Once introduced, non-native insects can decimate crops and forests. Invasive rodents are also disruptive—particularly on island ecosystems, where they are the leading cause of plant and animal extinctions. Exotic plant pests and diseases threaten U.S. food security, quality of life, and the economy.