Emerald Ash Borer

Emerald Ash Borer

The emerald ash borer (Agrilus planipennis), commonly referred to as "EAB", is an invasive wood-boring insect that infests and kills ash trees(Fraxinus spp.). The larvae are the damaging stage of this insect as they feed on the inner bark of ash trees, disrupting the flow of water and nutrients within the tree. The cumulative damage to the vascular system of the tree causes dieback, eventually leading to tree mortality. Infested ash trees usually die within 2-4 years. The half-inch long metallic-green adult beetles nibble on ash leaflets from late-May to August in Iowa. Native to Asia, EAB was first discovered in the U.S. near Detroit, Michigan in 2002 and is thought to have been introduced via wood packaging material. EAB has currently been detected in 36 states.

Known Distribution & Treatment

EAB has become quite prevalent since its discovery in Iowa in 2010. At this time over 90 counties in Iowa have been confirmed with this invasive insect in one or more locations. The Iowa Department of Agriculture & Land Stewardship (IDALS) tracks the spread of EAB throughout the state. See EAB county detection map for Iowa. If you live in Iowa and suspect an EAB infestation in a county not yet detected, please contact IDALS so it can be confirmed and documented.

Ash trees within 15 miles of a known EAB infestation are at high risk of attack. Preventative treatments are suggested to protect healthy and valuable ash trees within at-risk areas. See a map indicating a 15-mile radius around confirmed EAB detections. Iowa State University Extension and Outreach has a publication that includes control measures to consider in preventing and treating partially EAB infested ash trees. For more information, see Emerald Ash Borer Management Options .

EAB Quarantine

Iowa has a statewide EAB quarantine, therefore hardwood firewood and ash articles can legally move within Iowa’s 99 counties. While EAB is present throughout many parts of Iowa, people are encouraged to use locally-sourced firewood where it will be burned to help limit the spread of EAB to new areas. Buy local, burn local!

The USDA’s Animal Plant Health Inspection Service (APHIS) EAB federal domestic quarantine was eliminated in 2021. Due to the deregulation, some states have state-level exterior quarantines in place to restrict the movement of EAB regulated articles into their states. Some of these states still have little or no EAB. Regulated articles may include firewood of any hardwood species, ash logs, ash chips/mulch, ash trees, green ash lumber and tree debris of ash. It is important for individuals and businesses to determine if regulations exist prior to transportation of such articles. Contact IDALS for out-of-state certification requirements. With advance notice, opportunities may exist for a business wanting move EAB regulated articles to or transitting a state with an exterior quarantine.

Biological Control of EAB

Within EAB’s native range several species of parasitoids act as predators and play a role in maintaining lower EAB populations. These specialized parasitoids attack and ultimately kill the egg or larval stage of EAB. Due to their success of suppressing EAB populations, four species have been approved and introduced into the U.S. as biological control agents. Iowa is among a number of states utilizing this classical biological control approach. IDALS serves as a cooperator for the USDA EAB Biological Control Program. The parasitoids are produced and made available by the USDA-APHIS-PPQ Parasitoid Rearing Facility in Brighton, Michigan. The three types of parasitoids being released in Iowa are Oobious agrili, Tetrastichus plannipennsi and Spathius galinae. Contact IDALS for more information if interested in becoming a cooperator for the EAB biological control program in Iowa.

USDA's EAB Biocontrol Program Questions/Answers (.pdf)

Link - The role of biocontrol of EAB in protecting ash regeneration after invasion