Emerald AsH Borer on a leaf.

Emerald Ash Borer
Image Credit: USDA

CLEMSON — South Carolina officials have declared a statewide emergency quarantine of some wood products due the Emerald Ash Borer (EAB), an invasive insect pest that inhabits and destroys native ash trees.

Under the quarantine, the Department of Plant Industry (DPI) at Clemson University will regulate the interstate movement of wood and wood products that serve as hosts to the small, metallic green, wood-boring beetle. South Carolina will be added to the U.S. Department of Agriculture’s federal quarantine restricting the interstate shipment of all ash wood and wood products and all hardwood firewood.

The action follows a Sept. 29 public hearing in which landowners, timber industry professionals and state and federal officials gathered to discuss methods for dealing with the pest.

USDA detection traps revealed the insect in Spartanburg, Greenville and Oconee counties in August, marking the first discovery of EAB in South Carolina. The beetle, native to Asia, has now been detected in 31 states and Canada.

The pest was first discovered in North America in Michigan in 2002. It was detected in North Carolina and Georgia in 2013.

“EAB has been gradually progressing across the Eastern United States for 15 years,” said Steve Cole, director of Regulatory and Public Service Programs at Clemson. “At this point, the ecosystem is the greatest consideration. Quarantine will help us slow the spread of the insect to uninfected areas.”

The emergency quarantine will be in place statewide until the legislature can address the issue, Cole said. It covers transportation out of state of the EAB itself as well as nursery stock, green lumber and other material — such as uncomposted chips — from ash trees, the genus Fraxinus. It also applies to firewood of all hardwood (non-coniferous) species.

Regulated articles may be moved into South Carolina without state- or federally issued certificates or compliance agreements provided that no other state or federal provisions prevent it.

“We knew it was going to get here eventually. We’ve had a few close calls in North Carolina a mile or two from the border, so we had developed a preliminary plan for dealing with it,” said Steven Long, assistant director of Clemson’s Department of Plant Industry. “Eradication is not possible, but some level of control is. We are pursuing potential methods of biocontrol. There are parasitic wasps that target EAB. There are systemic pesticides you can use on high-value trees. But the reason this pest spreads so fast is that it has no natural predators here.”

The insect can fly up to 15 miles a year, an impressive feat for such a small bug, but it has spread so far largely with human help, said Tim Drake, state entomologist and a manager in Clemson’s Department of Pesticide Regulation.

“They are good flyers. They can spread easily, especially through the transport of infected wood,” Drake said. “I think it’s our responsibility to help prevent the spread to the uninfected areas of other states.”

“EAB is moving fast — a lot faster than the 15 miles a year that the insect can fly,” David Jenkins. forest health program coordinator for the South Carolina Forestry Commission, said at the Sept. 29 public hearing. “We have benefitted by seeing what it has done in other states. The quarantine will help protect the economic interests of people who have not yet been affected.”

Emerald Ash Borer is a member of the Buprestid family of insects, sometimes called jewel beetles for their iridescent metallic green color. EAB larvae feed on the inner bark of ash trees, blocking the trees’ ability to carry water and nutrients throughout their trunks and branches. They are responsible for the death or decline of hundreds of millions of ash trees since they arrived in North America.

Ash trees are important not only for their use as lumber and wood products, but also as ornamental trees. EAB damage frequently takes several years to be readily apparent, Drake said, so it is likely that infestation already has occurred beyond the three South Carolina counties in which the EAB has appeared in traps.

White ash, the variety found in Upstate South Carolina, is known for its strength. It historically has been prized for making tools and tool handles. About half the nation’s famous Louisville Slugger baseball bats are made from white ash.

Carolina Ash, green ash and pumpkin ash, which also thrive in parts of the Palmetto State, are targeted by EAB as well, said Don Hagan, a Clemson assistant professor of forestry and environmental conservation. Research shows the white fringetree, a popular ornamental tree in the same family as the ash tree, is also at risk, he said.

“We are not giving up on fighting EAB in South Carolina,” Long said. “We have an ongoing survey to continue to document the pest’s movement through the state and agents of the Clemson Extension service will be able to provide treatment strategies.”

More than 750 purple monitoring traps, which use chemicals to attract the adult EABs, hang in trees across the state.

Official information regarding the quarantine will be maintained and made publicly available soon on Clemson’s invasive species website clemson.edu/invasives.

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