An aggressive fight against an invasive grass has left a few roadside spots near Warren County highways blocked off and brown after powerful herbicides were used.

The Mississippi Department of Transportation has “been real aggressive” itself by eliminating areas of cogongrass on its rights of way, said Dr. John Byrd, a weed scientist with the Mississippi State University Extension Service.

Patches of ground along Interstate 20 and on parts of U.S. 61 are brown from the herbicide used to combat the grass, native to southeast Asia and present in 62 of the state’s 82 counties.

MDOT’s selective elimination focuses on blooms in small, specific areas, said Central District Engineer Kevin Magee.

“It’s a bad-news type of grass,” Magee said. “We get to it right as it starts making a head.”

About $5 million in federal assistance had been available in 19 Mississippi counties to help private landowners get rid of cogongrass, known for a circular growth pattern and dense roots. It has no natural enemies and it kills native vegetation by producing a toxin that stunts its growth. Animals don’t eat it, making it useless for grazing, and it is highly flammable in climates that match its Asian origins.

The federal money for cogongrass elimination are drying up quickly due to a generally unfavorable attitude in Congress about earmarks, Byrd said.

“We’d been fortunate the past few years to get money to help people treat their property,” Byrd said.

Traditional herbicide that kills the cogongrass and everything around it has been used on state rights of way in and around Vicksburg. However, MDOT’s use of herbicides that kill only invasive species and leave alone less aggressive grasses, such as bahia, is growing gradually, Byrd said.

“They’ve tried it around Hattiesburg, and it allows the bahia to live,” Byrd said.

The perennial grass was brought to the United States in 1911. It appeared near Mobile as packing material in plant shipments from Japan. Federal law prohibits its transport into and inside the U.S. Mississippi’s southeastern and coastal counties form the heart of cogongrass infestation in the state, according to the state Forestry Commission and Department of Agriculture and Commerce.