Voracious kudzu bugs spread across South. Are they boon or bane?

Somewhere near here, an uninvited guest – a nubbin-size stinkbug, like a tiny drab ladybug – arrived on America’s shores in 2009 and found, like invasive species that had come before, a bounty.

In this case, the so-called kudzu bug found kudzu – another Asian invader that has become the drapery of the South and has withstood all previous attempts, be they goat or chemical, to control “the vine that ate the South.”

But as the invading kudzu bug colony has metastasized across at least three states in a mere three years, the kudzu bug has developed a major downside. Their food preferences controlled, robot-like, by symbiotic bacteria, the bugs have suddenly begun to sink their “piercing-sucking mouthparts” into soybean leaves, as well, reducing yields by as much as half by stressing the plants.

Combined with its reputation as a strong flier and efficient hitchhiker (it likes white cars, especially), the bug has marched from Georgia through the Carolinas. Its movement has quickly drawn comparisons to that of the boll weevil, which nearly destroyed the Southern economy beginning in the 1920s after the insect jumped the border at Brownsville, Texas, in 1892.

“The door is sort of wide open: How far is this insect going to go?” says Dominic Reisig, an entomologist at North Carolina State University, in Raleigh. “If it moves into the Midwest and really likes it there, we’re in big trouble.”

At the same time, Mr. Reisig concedes, the kudzu bug invasion does have a definitive “silver lining” that’s become part of the broader academic debate about how, and if, to fight it in a systematic way.

One of the original invasive species, kudzu, a mispronounciation of its Japanese name, kuzu, is a floppy-leafed vine that covers some 8 million acres of countryside, mostly in Mississippi, Alabama, and Georgia, but which has been found as far north as Nova Scotia and in all five boroughs of New York City.

First used as erosion control by Southern farmers, kudzu, which can grow as much as a foot a day in the Dixie heat, quickly got out of control and was named a noxious weed by the US government in 1997.

Given the stubborn spread of kudzu’s choking vines, the arrival of the kudzu bug has left a small USDA lab in Mississippi having to make a tough decision. Government scientists have located a potential kudzu bug assassin – a parasitic wasp – but the question of whether to release it has pitted residents of southern Georgia against North Carolina farmers.

In North Carolina, where farmers now get as much as $14 a bushel for soybeans – compared with $6 a bushel a decade ago – the bug stands in the way of big paydays as soybean acreage has grown to nearly 2 million acres. But in south Georgia, where soybeans aren’t a major crop, the prospect of a kudzu killer that can cut back 30 percent of the plant’s biomass in a season could be a boon that many residents say should be encouraged.

The rapid spread of the kudzu bug has some longtime Southern scientists remembering the boll weevil epidemic that swept cotton fields, laying to waste family farms and local rural economies. The boll weevil has cost Southern farmers some $13 billion since it first entered the country in the 1920s, capable of traveling 160 miles per year. Its activity, too, was in part curtailed by a parasitic wasp, as well as the spread of fire ants, a natural boll weevil enemy.

First found in the Atlanta area in 2009, the kudzu bug had by last year encroached through most of South Carolina and is expected in most North Carolina counties this summer, as well as up to half of Virginia. It’s likely to have spread to Mississippi and Alabama, as well.

“The stakes are high for farmers, but [the bugs are] also a homeowner nuisance since they like to overwinter in houses,” says Professor Reisig. “The number of questions I’m getting from homeowners about kudzu bugs is ridiculous.”