Emerald Ash Borer


September 24, 2020: EAB Detected in Price County

September 10, 2020: EAB Detected in Florence County​

​August 12, 2020: EAB Detected in Dunn, Oconto, Pepin, and S​hawano Counties

Note: The entire state is part of the EAB federal quarantine area, so there are no regulatory changes as a result of these detections. Notification is sent when EAB is found for the first time in a county.


Emerald ash borer (EAB) is an invasive beetle introduced from Asia. It entered North America from China near Detroit, Michigan, probably on wooden packing crates. It was first detected in Wisconsin in 2008. Since then, we have detected it in 51 of Wisconsin’s 72 counties. Currently, the most severe EAB damage is concentrated in the southern half of the state.  There are still large areas where we have not yet detected EAB; only about a quarter of the state's municipalities have confirmed EAB infestations. In these areas, it may not be present yet, or it may be present in such low numbers that damage is not yet apparent.

EAB attacks all species of ash trees, except mountain ash, which are not true ash trees.

Reporting EAB

It is not necessary to report EAB in municipalities where we have already detected it. However, if you live in a county or municipality where we have not yet detected it, you should report it. To check your county’s detection status and report if necessary, visit our interactive map​ and type in your address. 

Life Cycle and Damage

Adult EAB beetles are active in late spring and early summer. They lay eggs on the bark, and the larvae, which are flat and worm-like immature beetles, hatch and burrow under the bark. The larvae kill trees by feeding on the wood immediately under the bark. This disrupts the tree’s ability to carry water and nutrients up from the roots and kills the tree from the top down. 

Quarantines and Firewood

You may have heard about the EAB quarantine over the years. For 10 years, we placed individual counties under quarantine when we detected EAB there. Now the entire state is under quarantine for EAB. 

When only some counties were quarantined, it was illegal to move some ash forest products and hardwood firewood from a quarantined county to a non-quarantined county. Because all counties are now quarantined, wood products can move more freely within the state. 

However, it is still illegal to move firewood and other regulated items out of state to non-quarantined areas. Even within Wisconsin, there are other restrictions on moving firewood due to gypsy moth quarantine regulations and rules for firewood on state, federal, and tribal lands. Details 

Because of these regulations, we strongly recommend that you either use DATCP-certified firewood, or buy it near where you will be burning it.  This will also help to prevent introducing EAB to new areas of the state, as well other pests and diseases.

Proposed Federal Deregulation

The USDA Animal and Plant Health Inspection Service has proposed removing the EAB quarantine nationally, now that this pest has spread to at least 30 states.  This would eliminate regulations on moving ash and other products between states.  Instead, resources formerly used for enforcing regulations would be directed toward managing EAB, particularly through biocontrol. This method uses tiny stingless wasps that are natural enemies of EAB.  

If this deregulation takes effect​, some western states would likely opt to enact exterior quarantines for EAB. This would restrict movement of ash wood products from Wisconsin to these states, so it will be important for businesses and individuals to check for changes to the regulatory landscape over the coming months.


Back to main plant pests and diseases page