Cogongrass newest pest

Published 5:00 am Wednesday, September 3, 2003

Kudzu has been Mississippi’s number one agricultural menace forat least a decade, but now it’s been replaced by a hardy, four-foottall grass from Asia.

The winner of that ominous title is commonly called Cogongrass,said Patrick Sullivan, bureau director for the Market DevelopmentDivision of the Mississippi Department of Agriculture. It has alsobeen designated as the seventh worst weed in the world.

Lester Spell, commissioner of the MSDA, announced a plan earlierthis month to wage war on this Southeastern import and said it”literally chokes out the living habitat for all other plants andanimals, creating a living dead zone.”

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Sullivan said the MSDA is asking for help from the public inattempts to eradicate this weed. The first step is to check yards,and if a weed is suspected to contact the MSDA or the MississippiState University Extension Service for confirmation. A resident canthen start trying to control the spread of the weed withchemicals.

“We recommend one application per year from late summer or earlyfall with follow-ups each year,” he said.

The most effective chemicals in combating Cogongrass have provento be Arsenal (imazapyr) and glyphosate.

“We’re not going to be able to totally eradicate it, but what wecan hope, and plan, to do is eradicate it in certain parts of thestate and control the spreading,” Sullivan said. “I thinkcontainment is the key word in the southern part of the state whereinfestation is widespread.”

Cogongrass is native to Southeast Asia, the Philippines, China,and Japan. It is a perennial grass that grows to a maximum heightranging from two to four feet. The leaves are about an inch wide,have a prominent white midrib, and end in a sharp point. The uppersurface of the leaf blade is hairy near the base and theundersurface is usually hairless.

Flowers typically occur at the top of the stem, and are easilyidentified by silvery or whitish silky hairs attached to the seed,creating the appearance of a feathery plume, according to a MSDAdescription of the weed.

It is also commonly known by the names japgrass, Japanesebloodgrass, Red Baron, or speargrass.

“It’ll replace natural habitat, pastureland, native grasses, andany non-cultivated soils,” Sullivan said.

Other key areas of infestation, he said, are orchards, fallowfields, forests, parks, and highway, utility, pipeline, andrailroad rights-of-way.

Cogongrass was both accidentally and purposefully introducedinto the southern U.S. around 1910 and into Mississippi, Alabamaand Florida around 1920 as pasture forage and for erosion control.Unfortunately, it did not make good livestock feed and was tooweedy for erosion control. It is also sold in the nursery trade asan ornamental grass.

In 1979, Cogongrass was found in 19 of Mississippi’s 82counties, mostly in the southern part of the state. By 2002,however, it had spread north and west until it now has beenidentified in 52 counties. It has infested all counties south of aline ranging northeast from Amite County to Lowndes County withinfestations in several other counties west of that line.

Sullivan said the weed is able to “out compete” native foliagebecause it is very dense above ground and it’s root mass “is justamazing.”

“To run a knife down into the soil to cut the root system out islike cutting chicken wire,” he said.

The grass is also very mobile in its seeding, adding to thedifficulty of stopping its spread. A seed head of Cogongrass cantravel up to 15 miles on a light breeze, he said. He compared it tothe way a dandelion will float on the wind.