Kudzu might meet its match in appetite of two insects Nuisance: Scientists use larvae of two bugs to eat the crawling vine faster than it can overtake the South.


GERMANIA SPRINGS, Ala. -- Now and again, Paul Williams will drive past a tangle of deep green kudzu vines and think how pretty it smells.

"It won't bloom unless it can climb, and it smells like grapes," said Williams, a 75-year-old farmer who is widely respected in this slow, lush corner of the world for his knowledge of important things, like good tomatoes, tall alfalfa and intelligent dogs.

He knows a bit about kudzu, too, a species of crawling weed introduced to the United States from Asia in 1876.

He knows that that grape-like smell means trouble.

"They planted it in the 1930s down here to control the erosion on the hillsides," said Williams, whose farm is in the foothills of the Appalachians in northeastern Alabama, about 100 miles west of Atlanta. "They gave it to these farmers. They put out a little bit, and the next thing you know, it was on their house.

"I've fought and fought that stuff" to keep it from taking over the fields and pastures, he said. Leave it alone, he said, "and that dang stuff will grow over the trees."

Over long decades in the South, kudzu has choked forests, swallowed power lines and even blanketed houses. In the process, it has woven itself into the very culture of the region.

Like the plant itself, the feelings for it are lush but tangled. Now there may finally be a way to stop its inexorable creeping.

Researchers from North Carolina State University in Raleigh have married nature and science in a scheme that might pose the first realistic threat to kudzu.

Those scientists use a common bug -- actually two species of insect larvae eating in tandem -- to kill the legendary weed.

For 50 years, farmers and scientists have tried and failed to find an effective, environmentally sound way to control it. It has no natural enemies in this country, and it requires such heavy doses of herbicide that farmers sometimes kill everything near it when they try to get rid of the weed.

Grows rapidly

In the South, where 7 million acres have been covered by kudzu, a plant can grow several inches in a day -- some say a foot a day.

"I have a slide I show at seminars of a Department of Transportation road grader that was parked on the side of the road for a few weeks, and it was completely covered in kudzu," said David Orr, a professor of entomology at North Carolina State who is one of the researchers responsible for this latest strategy.

"The driver," he said, tongue in cheek, "got out just in time."

To kill such a thing required imagination.

Importing a foreign species of insect can be dangerous because of the potential long-term effect on the environment.

Instead, the North Carolina State researchers have introduced the soybean looper -- a caterpillar usually found in soybeans -- into fields of kudzu, but not before they committed a little sabotage on those caterpillars.

To keep the soybean loopers from pupating into moths and destroying crops, researchers injected the caterpillars -- larvae themselves -- with eggs from a stingless wasp. The eggs hatched into wasp larvae, which not only killed the caterpillars from within -- slowly -- but caused them to eat more rapidly than normal.

"The caterpillars eat about one-and-a-half to twice as much as they normally would, which is good for us" and terrible for the kudzu, Orr said.

The wasp larvae -- each egg can contain hundreds of them -- "sit there like little time bombs until the last growth stage of the caterpillars," Orr said. "They don't kill the caterpillars until they spin their cocoon to get ready to pupate" into moths.

This most recent strategy in the war on kudzu, financed by a grant from the U.S. Forest Service and federal Department of Energy, has been successful in tests in the Carolinas.

It might be soon be used to kill kudzu in more remote places in national forests where heavy equipment or poison would threaten the surrounding plants or wildlife.

"They left the natural enemies of the plant behind in China," where it originated, Orr said. "It takes a 55-gallon drum of herbicide to kill just one acre, and even then you don't really kill it," he said. It comes back.

Roots run 10 feet deep and can weigh 200 or more pounds per plant.

Controlling the looper

The looper was not known to be a threat to kudzu, at least until a woman in Union, S.C., noticed them feeding on the weed there. That, to make a long and complicated scientific story short and simple, got researchers like Orr to thinking.

If they could control the loopers, they could, perhaps, control the kudzu.

But first they would have to introduce the loopers to the kudzu on a wider scale.

Kudzu, "the Southern menace," beaten?

"Kudzu stands by itself" in the mystique of weeds, said Bob Thomas, chairman of environmental communications at Loyola University in New Orleans and a senior scientist at the Audubon Center for Research of Endangered Species.

People will tell you they can see it grow.

"It covers tractors, barns, telephone poles and slow-moving children," said Doug Marlette, the creator of the comic strip "Kudzu," about life in the shade of its vines in a small Southern town. He is also a Pulitzer Prize-winning cartoonist for Newsday.

"Even if you intellectually know it probably can't happen, it's a little scary," Thomas said. "I have had restless nights camping out around kudzu."

In Louisiana, "the way you handle something down here is you eat it," Thomas said. "But you'd have to eat fast," and kudzu has never really caught on as a food source for humans.

For now, it is contained largely in the South, although it has crept as far as New York City.

But the Yankees, say Southerners who have lived beside it, will never appreciate its mystique.

In the stage play, "Kudzu, a Southern Musical," adapted from Marlette's comic strip, there is even an ode to it:

Kudzu is everywhere.

It covers us from here to there.

It's who we are.

It's our destiny.

Kudzu's a friend of mine.

Doggone climbing vine.

Cheap green suit

from the mountains to the sea.

Pub Date: 9/07/97

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