Emerald ash borer beetles have been discovered in Delaware, making it the 28th state to have found the insect, the Delaware Department of Agriculture announced.

Emerald ash borer beetles have been discovered in Delaware, making it the 28th state to have found the insect, the Delaware Department of Agriculture announced.

The statewide impact of the destructive, invasive beetle is expected to be minimal, as ash trees make up only around 2 percent of Delaware's tree stock. The state has also been preparing for more than a decade. State forestry and plant health officials are providing advice to homeowners, municipalities and civic groups at de.gov/ashtrees.

"Because this was not unexpected, we have been working for several years with cities, towns and civic groups on plans to manage and replace ash trees," said Faith Kuehn, administrator of DDA’s Plant Industries Section, which oversees EAB detection, control and prevention in partnership with the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service.

Delaware will be added to a federal quarantine already in 27 other states restricting the interstate shipment of all ash wood and wood products — ash nursery stock, green lumber, waste, compost and chips — as well as hardwood firewood of all species. Some shipment out of state may be permitted if certain requirements are met and a federal permit is issued.

Kuehn and State Forester Mike Valenti said the effect on businesses and public lands should be small. Most retail garden centers don’t offer ash trees, Kuehn said.

Emerald ash borer only attacks ash trees and a close relative of ash, the white fringetree. There are virtually no ash trees at Redden State Forest, while ash makes up about 0.1 percent of trees at Blackbird State Forest and less than 0.01 percent at Taber State Forest.

The beetle was found in a trap placed in an ash tree in New Castle County. Emerald ash borers can travel to new areas by natural means, as well as on firewood, timber and nursery stock. The emerald ash borer feeds under ash tree bark during its larval stage, which damages and eventually kills the trees. Adult EABs emerge in the spring and mate shortly thereafter, with each female laying 60 to 90 eggs in a lifetime. In the spring, pupae transform into adults and emerge through "D"-shaped exit holes.

Symptoms of an EAB infestation may not be apparent immediately, with damage taking up to three years to be visibly detectable. Symptoms, which can take up to three years to be visible, can include branch dieback in the upper crown, vertical bark splits, and small shoots on the trunk, as well as woodpecker damage.

Delaware has been working to monitor for emerald ash borer infestations since 2004, using both visual surveys and baited traps that attract the insects. Grant funding from the U.S. Department of Agriculture has supported both monitoring and forest pest outreach efforts.  

Delaware State Parks will continue to ban out-of-state firewood.