The emerald ash borer has been identified in a residential tree in the city of Creston, the fifth Iowa location in which the presence of the tree-killing beetle has been confirmed.
Emerald ash borer infestations “are definitely building in the state,” said Department of Natural Resources forest health specialist Tivon Feeley.
State officials confirmed the infestation in southwest Iowa’s Union County after an arborist alerted them to a suspect tree, State Entomologist Robin Pruisner said Thursday morning during a telephone news conference.
Investigators found characteristic galleries and D-shaped exit holes in dead branches, and a partial adult beetle was positively identified, she said.
“I think we’re seeing the culmination of an EAB population that is finally large enough to detect, coupled with trees readily showing symptoms because of multiple stresses in recent years, including EAB, drought and floods,” Pruisner said.
Following an initial Iowa confirmation in Allamakee County in May 2010, three years passed before the burst of confirmations this year: Des Moines County in July, Jefferson County in August, Cedar County in October and Union County this month.
DNR state forester Paul Tauke said additional confirmed infestations could be forthcoming. “We have a lot more people trained to look for it, and if it is out there, we are more likely to find it,” he said.
Pruisner said officials presume that transportation of infected firewood is spreading the plague. “It’s hard to find a smoking gun when the infestation if 4 to 5 years old,” she said.
A quarantine restricting movement of hardwood firewood, ash logs, wood chips and ash tree nursery stock was implemented Nov. 1 in 25 Eastern Iowa Counties. Pruisner said officials are developing an additional quarantine in response to the latest infestation. All options, including a statewide quarantine, “are on the table,” she said.
According to the USDA Forest Service, Iowa has an estimated 52 million rural ash trees.
DNR state urban forester Emma Hanigan said Iowa has about 3.1 million ash trees in urban areas
Given an estimated average tree removal cost of $1,000, Hanigan said the affliction’s cost to Iowans would likely be “in the billions.”
DNR Forestry Bureau personnel have completed 242 urban tree inventories in Iowa, in communities with fewer than 5,000 residents. Statewide, about 17 percent of the trees on city property are ash.Preventive treatments next spring — mid-April to mid-May — are available to protect healthy and valuable ash trees within 15 miles of the known infested area, said ISU Extension and Outreach Entomologist Mark Shour.