Emerald ash borer (EAB) was discovered in Sioux City for the first time in January 2023. Insect samples were collected by Iowa Department of Agriculture and Land Stewardship staff from ash trees in Sioux City (Woodbury County). Federal identification confirmed these samples positive for EAB. Since its original detection in 2010, the invasive, ash tree-killing insect from Asia has now been confirmed in all but three of Iowa’s 99 counties.

EAB is a significant threat to native ash tree species, typically killing a tree within two to four years after becoming infested. The cumulative damage by the larvae (immature stage) feeding on the inner bark eventually kills ash trees. The feeding cuts off the tree’s ability to transport water and nutrients.

In 2021, the City Council approved an Emerald Ash Borer Management Plan. The pro-active plan also included the approval of $1 million dollars to implement the plan and begin the process of removing ash trees on city-owned properties, including public right-of-way. In anticipation of the arrival of EAB, the Sioux City Parks and Recreation Department has performed the following:

• Hired two full-time parks staff to manage the EAB program and assist with tree removals on city-owned properties.
• Parks staff attended trainings on EAB management strategies.
• Created the EAB Management Plan for Sioux City.
• Worked to reduce the amount of ash trees on city-owned properties and public right-of- way and to diversify the tree species that were replanted.
• Contracted for the removal of sixteen 24” ash trees in the Mid-Town and Near Northside neighborhoods.
• Partnered with the Arbor Foundation to offer a free tree give-away.

PROPERTY OWNERS
Now is the time to decide a course of action for ash trees at risk of EAB infestation. The Emerald Ash Borer Management Plan provides information regarding the methods property owners can utilize to remove or treat their ash tree(s).
Management Plan highlights include:

• Remove declining ash trees and replace them with other species or use preventive insecticide treatments to preserve and protect valuable and healthy ash trees.
• The best time to treat for EAB is in the spring, from mid-April to mid-May.
• Iowa State University Extension and Outreach has produced a publication about EAB treatments. https://store.extension.iastate.edu/product/13114

The City of Sioux City will continue to monitor and inform residents of any new developments.

Email City staff with additional questions that arise after reading the City of Sioux City Emerald Ash Borer Management Plan.  

ISU Extention Press Release - January 19, 2023