The culprit is cogongrass, which grows in thick circular patterns and chokes native vegetation, says Bill Baisden, assistant state forester at the Alabama Forestry Commission. The blades of cogongrass are sharp-edged and highly flammable, and they can grow in dense mats, making it nearly impossible for other plants to coexist.

The grass has a high silica content, which means livestock won't feed on it. It has no natural controls in this country.

"Once it establishes itself, it just takes over," Baisden says. "It wrecks wildlife habitat. It's very easily spread. It can grow to 5 to 6 feet tall. It burns at a faster and hotter rate than our native grasses."

Cogongrass has caused such harm in Alabama that the state is using about $6 million in federal stimulus money to map the locations of the weed and eradicate it with herbicides, Baisden says.

What's at stake for the state: protecting its $43 billion farming industry and its timber lands. The Alabama Invasive Plant Council, estimates that productivity losses in forests that have been infested with the grass are in the millions.

The grass is not just in Alabama. It grows in Georgia, Louisiana, South Carolina, Tennessee and Texas, according to the Center for Invasive Species and Ecosystem Health at the University of Georgia. Anywhere from 1 million to 1.5 million acres are covered by the grass in the region, the center reports.

Cogongrass is believed to have been introduced by accident through the Port of Mobile in the early 1900s, Baisden says. It was used as packing material in shipments from Asia to the USA. The invasive grass was initially confined to the coastal counties of Alabama, Mississippi and the Florida Panhandle. Then came Hurricane Ivan: The September 2004 storm brought cleanup and recovery help from several states, including Texas and Tennessee, Baisden says.

"We had crews come in from states throughout the region. All that equipment moved earth for weeks, and sometimes months. Then they went home, and carried cogongrass roots and seeds with them," Baisden says.

Fast forward to 2009 and several of these states now are launching their own defenses against cogongrass:

• In Florida, the Department of Transportation created a database of cogongrass spots along highway rights of way using Global Positioning System mapping technology, communications director Dick Kane says. The grass has been found throughout Florida. "We are trying to map the locations of cogongrass so our maintenance crews … can take precautions against spreading the grass," Kane says. "If they mow a spot and don't clean the equipment thoroughly, all they are doing is spreading the grass."

•In Mississippi, officials are educating property owners about how to get rid of the grass, says Benny Graves, cogongrass expert at the state's Bureau of Plant Industry. "You can have a spot on your property and treat it, but if your neighbor across the fence has 40 acres of cogongrass, and they don't treat it, you're wasting your time and money."

•In South Carolina, where 10 of 46 counties report cogongrass infestation, an army of 200 volunteers are identifying the weed and controlling it with herbicide, says Steve Compton, invasive species coordinator for Clemson University's Department of Plant Industry.

Herbicides are the best way to control the spread of cogongrass, says Ernest Lovett of Larson & McGowin, a forest management firm in Mobile, Ala. The control effort includes everything from portable backpack sprayers to more elaborate rigs on ATVs and large tractors. Sometimes the battle can be daunting.

"You fly over the west part of the state and some pastures look like they have the measles," says Tom Lang, forester for Dallas County, Ala., referring to the circular growing pattern of cogongrass.

Roney reports for The Montgomery (Ala.) Advertiser

Enlarge By Mickey Welsh, The Montgomery (Ala.) Advertiser Stephen Pecot, with Larson & McGowin land managers, left, and Jamie Thomas, a forester with IndusTree Timber, right, examine some cogongrass near Sardis, Ala.