The emerald ash borer (EAB) is a destructive wood-boring beetle that attacks and kills ash trees (Fraxinus spp.). Adult EAB lay eggs on the bark of ash trees, and then larvae burrow into the bark. The larvae tunnel below the inner layer of bark, disrupting the flow of water and nutrients within the tree. The cumulative damage typically kills a tree within four years. Native to Asia, EAB was first discovered in the U.S. near Detroit, Michigan in 2002 and has since spread to over 35 states. This tiny insect is responsible for widespread ash tree mortality in Iowa and many other states.

Since October 2024, EAB has been confirmed in all of Iowa's 99 counties. Damage to ash trees in ongoing. The Iowa Department of Agriculture and Land Stewardship (IDALS) has been recording the spread of EAB since its initial finding in Iowa in 2010. See EAB county detection map. IDALS has continued to issue news releases for all first county detections through the years. The latest news releases include:

Early symptoms in EAB infested trees are present in the upper third canopy of the tree. A common observed indicator is canopy thinning and dieback. These symptoms will gradually progress downward over time. Other indicators may include 1/8 inch "D"-shaped exit holes, vertical splits in the bark, "S"-shaped feeding galleries in the vascular tissue beneath the bark, woodpecker damage to the bark, and leafy sprouts on main branches. A tree in significant decline will likely exhibit one or more of these symptoms on lower branches or main trunk.

Ash trees are a commonly planted landscape tree in Iowa. Preventative treatment can be used to protect reasonably healthly at-risk ash trees which are valuable to the landscape. Treatment may also provide protection on lightly infested trees, provided the damage is minimal. Without ongoing treatment, untreated trees will eventually succumb to EAB. Further information regarding treatment and management considerations can be found within the Iowa State University Extension & Outreach publication link below.

The EAB federal domestic quarantine was ended by USDA-APHIS several years ago. However, each state has its own laws, and it is important for individuals and businesses to determine if regulations exist prior to transporting EAB regulated articles outside of Iowa. Regulated articles may include firewood of any hardwood species, ash logs, ash chips/mulch, ash trees, green ash lumber and tree debris of ash. Contact IDALS for assistance with regulation status in other states.

While the restrictions on moving firewood within Iowa have been lifted, people are strongly encouraged to use firewood from local sources and 'Buy it Where You Burn it'. The use of locally sourced firewood can help prevent the inadvertent spread of damaging tree insects and diseases which can hitchhike in firewood.