Emerald Ash Borer

Emerald Ash Borer (EAB), an invasive beetle that kills all species of ash trees, has been confirmed in Polk County. It is native to Asia and was likely introduced into North America via cargo ships or planes. The beetle is bright metallic green in color and is visible to the naked eye, but is about the size of Abraham Lincoln’s head on a penny. The adult beetles eat ash foliage but cause little damage to the tree. It is the larvae that cause destruction. Larvae feed on the inner bark of ash trees, preventing delivery of water and nutrients to the tree, causing it to die. 

The Emerald Ash Borer has been confirmed in a number of Iowa counties. The Pleasant Hill Parks Department is happy to assist you in preparing for EAB with guidance from the experts at Iowa State University Extension & Outreach. For EAB treatment options, the City of Pleasant Hill recommends you contact a licensed professional. 

It is estimated that there are nearly 1,000 ash trees on private property within Pleasant Hill. We advise owners of ash trees to take action and plan for either removal or treatment. 

Chemical Treatment Options 

Trunk Injections - Of the three chemical options, trunk injections are generally the preferred option within the industry. Professionals recommend treating healthy ash trees because injections are absorbed and distributed throughout the tree quickly (typically 1 to 4 weeks), and are very effective. Research has shown that tree injections are tolerated in healthy ash trees, especially if treatments are applied once every two years. Experts advise rotating the annual trunk injections with other management options to decrease long-term damage. 

Soil Injections - Also commonly known as basal drenches should start when trees are still healthy because large trees are not protected well in the first year after basal soil drenches. Basal drenches typically take 4 to 8 weeks to absorb and should be done beneath the soil surface 2 to 4 inches and 12 to 18 inches from the trunk. These injections are not as readily used as trunk injections because of excessively wet or frozen soil, compacted sites, or restricted surface areas. 

Canopy Sprays - Not recommended due to the effectiveness, the need for special equipment, and possible adverse effects to non-target organisms. 

Tree Removal 

Tree Removal
 - Removing ash trees may be necessary if it appears damaged, unhealthy, or susceptible to EAB. Click here to compare local costs of treatment options or tree removal. 

For more specific information, refer to the links below.

Signs and symptoms of EAB

Treatment options