Tiny bugs take a bite out of La. marshes

Way to stop pests eludes scientists trying to save land

A swarm of tiny bugs with an enormous appetite has invaded the Louisiana marsh, and the pests are sucking the life out of vegetation that helps keep the state’s fragile coast from further dissolving into the sea.

Scientists and agricultural experts are teaming up to stop the parasites from destroying roseau cane, but they’re beset by a major problem: They don’t know what the bug is, so they don’t know how to attack it, and their early ideas — fire, insecticides and possibly the release of a wasp that preys on the bug — will likely result in side effects.

Louisiana State University entomologist Rodrigo Diaz said researchers only recently discovered the foreign family of insects to which the invasive species belongs, called Aclerdidae, which is native to Japan and China. But lab tests that identified it couldn’t reveal how it arrived — on a ship, attached to a migrating bird or even on the wind.

What’s certain is that a team of surveyors checking the cane that comes in various shades of green found stalks bent in water, brown and dead in the mouth of the Mississippi River. That’s when they began to notice significant die-offs of four varieties of cane and more open water in the hundreds of acres the cane once occupied. Two to three years before, there was a thick, unrelenting wall of marsh.

“They are feeding on it,” said John Andrew Nyman, a professor at the School of Renewable Natural Resources at LSU. “The bugs suck the sap out. The leaves are trying to send sugar to the roots, and they suck out so much that the plant can’t function. It dies.”

The mealy bug, as it’s also known, adds to the invasive insects that have made their way to the United States from Asia and Europe.

Animals that have ruined plants and crops include the brown marmorated stink bug, the kudzu bug, the emerald ash borer and aphids that are threatening Florida’s citrus industry and wreaking havoc on Christmas tree pines from West Virginia to North Carolina.

The Louisiana cane is crucial to staving off land loss. It builds soil in an area that lost 250 square miles of coast to erosion and sinking land over a half-century.

Diaz said experts are weighing options to fight the threat. An idea for a controlled burn is derived from China, but the Louisiana coast has a network of oil and gas wells that could explode in flames.

Maybe the parasite’s natural predator, a tiny wasp from Asia, can be employed.

However, it takes years of study before a new species can be released, for fear that the wasp might turn on native animals.

“What you could end up with in 10 years is the bugs will die back,” Nyman said, after killing all the cane. “They’ll become a smaller part of the landscape, both the bug and the plant.”