Landscape Services staff keeping eye on beetles lurking across state borders

An invasive beetle that feeds on—and eventually kills—ash trees has been discovered just across Iowa’s borders with Wisconsin and Minnesota. Given that the University of Iowa campus has between 700 and 800 ash trees on maintained areas of campus, an infestation of the emerald ash borer could pose a significant risk to the UI campus landscape.

The emerald ash borer. Photo by Rob Meinders, USDA APHIS PPQ.

The Landscape Services staff in Facilities Management is monitoring the situation and will take appropriate steps to develop a response plan.

The University’s ash trees comprise roughly 10 percent of the campus tree population; some notable areas with ash trees are the east side of Main Library and in the Carver commuter parking lot.

“Some municipalities would be in a lot worse shape with upwards of 35 percent of their trees being ash,” says campus arborist Andy Dahl. “This speaks well of the diversity of our urban forest.”

The emerald ash borer kills all ash (Fraxinus) species by larval burrowing under the bark and eating the actively growing (cambium) layers of the trees. Ash is one of the most abundant native tree species in North America, and has been heavily planted as a landscape tree in yards and other urban areas.

Officials from around the state have formed the Iowa Emerald Ash Borer Team. The team is working to ensure that the beetles do not spread into Iowa by examining high-risk sites where people would bring out-of state wood, such as campgrounds, nurseries, and sawmills.

“This insect is spreading almost entirely by human activity, so stopping the transport of ash products is of utmost importance,” Dahl says.

Areas currently infested are under federal and state quarantines, but unknowing campers or others who transport firewood can spark an outbreak. Team members will be working with Wisconsin and Minnesota officials to conduct additional visual surveys in the coming weeks.

Control strategies will depend on the size and scope of an initial infestation and how many ash trees are nearby. Everything from continued monitoring and scrutinizing of the campus ash tree population, clear cuts of ash, and setting traps will be considered.

by Wendy Moorehead, UI Facilities Management