EAB pest damage is confirmed in Del. trees

DOVER, Del. (Aug. 30, 2016) — A destructive, invasive beetle that kills ash trees, the emerald ash borer, has been confirmed in Delaware, making it the 28th state to have found the insect, the Delaware Department of Agriculture announced last week.
The statewide impact is expected to be minimal, as ash trees make up only around two percent of Delaware’s tree stock and the state has been preparing for more than a decade. State forestry and plant health officials are providing advice to homeowners, municipalities and civic groups at, where they can find information, fact sheets, photographs and links to other resources.
“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 Dr. Faith Kuehn, administrator of DDA’s Plant Industries Section, which oversees EAB detection, control and prevention in partnership with the USDA’s Animal and Plant Health Inspection Service.
Kuehn said that with surrounding states all having confirmed emerald ash borer finds, it was only a matter of time before Delaware had its first detection. DDA staff members have also worked to educate residents, visitors and campers about the importance of not bringing firewood into the state that could bring EAB and other pests. “We understand people have questions about the health of their trees, and we are answering them,” she said.
Delaware will also 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 Dr. Mike Valenti said the effect on businesses and public lands should be small.
“Because we have had time to prepare, nursery growers and wholesale nursery stock distributors have either eliminated or reduced their ash inventory, and most retail garden centers do not offer ash trees for sale,” Kuehn said. She advised nursery businesses that choose to continue selling ash trees to examine the stock upon arrival, and nurseries and landscapers should continue to examine branches and trunks for signs of emerald ash borer infestation.
Emerald ash borer only attacks ash trees and a close relative of ash, the white fringetree, so homeowners should not be concerned that other trees or plants will be affected, said Valenti, whose staff manages Delaware’s state forests, urban forestry and forest health programs.
“There are a variety of other trees that we recommend homeowners and land managers plant in place of ash trees,” Valenti said. “Thankfully, ash trees are not a major part of Delaware’s forest landscape, and there will be little impact on state forests.” 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 can include branch dieback in the upper crown, vertical bark splits, and small shoots (epicormic branching) 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.