emerald ash borer killed millions of ash trees found in Cumberland County

An invasive beetle that has decimated ash trees across the country and in much of North Carolina has been found in Cumberland County, and there's little to nothing officials or property owners can do to stop its spread.

The emerald ash borer, a strikingly beautiful member of the insect family, isn't supposed to be here. Native to Asia, the pest was first spotted in the U.S. near Detroit in 2002. The bug likely hitched a ride over the Pacific in wood-packing material carried by ships or planes.

Today, the metallic green beetle has been spotted in more than 40 states and Canadian provinces, killing hundreds of millions of ash trees, and it is slowly colonizing North Carolina. The bug is now found in 71 of the Tar Heel State's 100 counties, most recently seen in Craven and Hertford counties. Prior to that, it was detected in Cumberland and Lee counties.

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"It's moving fairly rapidly," said Jim Moeller, a forest health specialist with the N.C. Forest Service, "and there's really no way of stopping it."

The mature beetle, which is about half-inch long, isn't the tree killer, but its larvae is. Adult borers lay their eggs on the bark of ash trees. When the eggs hatch, the larvae bore into the bark and feed on the tree's transportation tissue. What follows is a slow, top-down death for the ash tree, as first the crown of the tree is starved of water and nutrients and then the rest of the tree − a process that can take up to five years.

Moeller said it's often hard to spot a borer attack for someone who isn't a horticulturist because the first signs often occur at the top of the tree, and ash trees can grow more than 80 feet tall. The telltale signs of an infestation on the bark also isn't something most people are out looking for on a regular basis.

"By the time most folks do see it, we're already behind the curve so to speak," Moeller said. That includes an unusual amount of woodpecker activity at a tree, since the birds will be going after the beetle larvae that have already infected the tree.

While the beetle can fly to expand its range, Moeller said most of the invasive bug's spread is due to human transport of infected trees and wood to other counties and states. Because of that, the entire state of North Carolina is under a quarantine for the ash borer which prohibits the movement of ash plant parts, the insect itself, ash nursery stock and all hardwood firewood.

"That's our message to people: if you're going to burn, buy local and burn local. Don't buy wood in Bladen County and take it down to the beach with you," Moeller said.

The bugs also use waterways to travel, since many ash trees are found around rivers and wetlands. Moeller said the infected trees in Cumberland and Bladen counties were discovered along the banks of the Cape Fear River.

Ash trees only make up about 2%, about 250 million trees, of North Carolina's forest stock, according to the latest survey. But Moeller said the hardwood is valuable to property owners and industry, used to make everything from tool handles and furniture to several versions of the popular Louisville Slugger baseball bat. Ash trees also serve as important habitat for a host of birds, animals and insects and add diversity to the state's forests.

Since first spotted in Granville County north of Durham in 2013, the invasive pest has spread quickly. Moeller said the march of the ash bore is adding four or more N.C. counties a year.

Active ways to stop the beetle's spread are few, with researchers around the country − including at N.C. State University − looking into using biological controls from the ash borer's home turf in Asia, including tiny wasps that feed on the bug's larvae.

Ash trees also can be treated before and after they've been infected, but the treatment options are expensive and have to be done repeatedly to protect the trees.

Moeller said If property owners see or believe they have an infected tree, they should contact their local forest service office so rangers can track the pest's spread.

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Dr. Jim Gregory, a retired forester with N.C. State University and a member of the Alliance for Cape Fear Trees, said while ash trees aren't as common in the state's coastal plain as they are in the mountains and Piedmont areas, they do fill an important economic and ecological niche in Southeastern North Carolina.

"This is a very serious pest and it's marching this way," Gregory said, noting that the ash borer also has been known to attack ornamental white fringe trees as well as the state's four species of ash.

And hopes of stopping it?

“It's going to get here," Gregory said of the ash borer's trek to the coast. "It's so close now. It’s evitable."

Reporter Gareth McGrath can be reached at [email protected] or @GarethMcGrathSN on Twitter. This story was produced with financial support from 1Earth Fund and the Prentice Foundation. The USA TODAY Network maintains full editorial control of the work.