Kudzu is an invasive plant species in the United States, introduced from Asia with devastating environmental consequences, earning it the nickname "the vine that ate the South". It has been spreading rapidly in the Southern United States, "easily outpacing the use of herbicide, spraying, and mowing, as well increasing the costs of these controls by $6 million annually". Estimates of the vine's spread vary, from the United States Forest Service's 2015 estimate of 2,500 acres (1,000 ha; 10 km2) per year to the Department of Agriculture's estimate of as much as 150,000 acres (61,000 ha; 610 km2) annually.