Invasive emerald ash borer makes its way into Chatham

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PITTSBORO — Emerald ash borer (EAB) was recently discovered in Chatham County for the first time, making Chatham the 41st North Carolina county in which the invasive insect has been detected.

The EAB — a metallic green beetle that bores into ash trees, feeding on tissues beneath the bark, ultimately killing the tree — was found along Wilkinson Creek between Chapel Hill and Pittsboro on traps to detect the beetle placed by the N.C. Forest Service.

“They can be very devastating,” said Ben Baird, a Chatham County Ranger with the state Forest Service.

Baird said the beetles, a non-native species originally from Asia, have been slowly migrating into the region. The beetle was first discovered in the United States in southeastern Michigan, near Detroit, in the summer of 2002, according to the website emeraldashborer.info. EAB is believed to have arrived in the United States via solid wood packing material carried in cargo ships and airplanes originating in its native Asia.

Emerald ash borers and have now been found in many North Carolina counties, including Alamance, Avery, Buncombe, Cabarrus, Caswell, Catawba, Chatham, Davidson, Davie, Durham, Forsyth, Franklin, Gaston, Graham, Granville, Guilford, Halifax, Haywood, Iredell, Jackson, Johnston, Lenoir, Lincoln, Macon, Madison, Mecklenburg, Mitchell, Orange, Person, Polk, Randolph, Rockingham, Rowan, Surry, Swain, Transylvania, Vance, Wake, Warren, Wayne, Wilson and Yancey.

The signs and symptoms of the presence of EAB aren’t always immediately noticeable, state forestry officials said, because EAB damages the inside of the tree. Adult borers lay eggs on the bark of ash trees and when their eggs hatch, the larvae bore into the bark and feed on the transportation tissues of the tree, disrupting the movement of nutrients and water within the tree, causing the tree’s slow death. Affected trees — often those found alongside rivers, Baird say — typically succumb to the EAB damage within three to five years.

Signs and symptoms of EAB infestation include thinning and dying crowns; increased woodpecker activity that causes the affected tree to look like it is losing patches of bark; small, 1/8-inch D-shaped exit holes where adult beetles have emerged from the trees; galleries on the inside of the bark; cream-colored larvae; and epicormic sprouting, or sprouting from the main stem of the tree. Plants susceptible to the EAB include all native ash trees and native white fringetree. The Chinese white fringetree, frequently planted for ornamental purposes, is believed to be resistant.

Forestry officials said the entire state of North Carolina is under a quarantine for EAB. The quarantine prohibits the movement of ash plant parts, the insect itself, ash nursery stock and all hardwood firewood into non-quarantined areas such as central Tennessee, most of Alabama and all of Florida.

Adult EAB beetles are about a half-inch long and 1/8-inch wide. If their wing covers are pried up, their bodies are a metallic purple-red color. In North Carolina, the adult EAB is typically active from late spring and early summer, likely April through June. EAB larvae, however, may be found under the bark of the tree most of the year.

The North Carolina Forest Health Branch monitors the spread of invasive pests, including EAB. Chatham residents who suspect an infested tree in an area near them are asked to contact the county ranger at 919-545-2720.

Randall Rigsbee can be reached at rigsbee@chathamnr.com.