Emerald Ash Borer

emerald ash borer

Emerald Ash Borer has been confirmed throughout most of eastern Iowa. A map of the counties affected can be found here: EAB in Iowa Map

EAB Resource Guide

02/04/2014 - Emerald Ash Borer state-wide quarantine announced – The Iowa DNR and IDALS announced a quarantine for the entire state of Iowa. Even though Iowa has been quarantined statewide, Iowans are encouraged not to transport firewood across county or state lines, since moving firewood poses the greatest threat to quickly spreading EAB or possibly other pests even further.

Emerald Ash Borer (Agrilus planipennis) is a small green invasive wood boring beetle that attacks and kills ash trees. The adults live on the outside of ash trees feeding on the leaves during the summer months. The larvae look similar to white grubs and feed on the living plant tissue (phloem and cambium) underneath the bark of ash trees. The trees are killed by the tunneling activity of the larvae under the tree's bark, which disrupts the vascular flow.

The metallic green beetle is native to East Asia and was imported to the United States within the wood of shipping crates from China. Emerald Ash Borer (EAB) was first discovered in North America near Detroit, Michigan in 2002. Since the first discovery it has also been found in many states and in Canada.

EAB attacks native ash trees of any size, age, or stage of health. Millions of ash trees have already been killed in infested areas. Much of Iowa's forestland is densely populated with ash trees, and Iowa's community street trees are heavily planted with ash cultivars. Early inventory data indicates that there are 52 million woodland ash trees and 3.1 million urban ash trees. Take a moment to think about how many ash trees are in your yard, neighborhood, community, and woodlands. Then imagine those areas without ash trees. Trees that have been attacked by EAB can die within 2 years.

Research has shown that EAB can only fly a few miles, which helps slow its natural spread. However, it is easily transported to new areas when people inadvertently move emerald ash borer larvae inside of infested firewood, ash nursery stock, and other ash items. Please do not move firewood from infested areas into non-infested areas. 

Iowa DNR Forestry Bureau does not recommend using imidacloprid drenching for treating Ash trees for EAB. For more information please refer to the PDF below titled Potential Side Effects of EAB Insecticcides FAQ.

What Does EAB Look Like?

EAB Larva


Emerald ash borer adults are small, metallic green beetles that are 1/2 inch long and 1/8 inch wide (smaller than a penny). 

Adult emerald ash borers emerge from beneath the bark of ash trees in May through mid-July, creating a D-shaped exit hole. Adult beetles are most active during warm sunny weather. They have a limited distance they can fly (1 mile to 4 miles) depending on the wind. 

Once they find a mate, the female can lay 60 - 90 eggs in the crevices of ash tree bark. Adult beetles will feed on ash tree leaves creating "notches" that does not harm the tree. It is estimated that adult beetles live up to six weeks after emergence. 

Larvae (immature stage of EAB) 

Emerald ash borer larvae are white and slightly flattened, with a pair of brown pincher-like appendages called urogomphi on the last abdominal segment.Their size varies as they feed under the bark on the ash tree's tissues and grow. Full grown larvae average 1.5 inches in length. EAB larvae feed in a S-shaped pattern, which is a diagnostic characteristic to this pest.

What does Ash look like?

All of the ashes have opposite-branching and pinnately compound leaves which almost immediately identify them. The ashes have five or more leaflets. The seeds look like miniature canoe paddles -- a double samara

Opposite branching. 

ash opposite branching

Compound Leaf

ash compound leaf

Quilted Bark

ash quilted bark


ash seeds


do not move firewood sign

Firewood can harbor many different kinds of invasive pests and diseases that are harmful to Iowa's trees. Asian longhorned beetle,emerald ash borer, gypsy moth, oak wilt, and sirex wood wasp are just a few pests that can be transported on firewood.

The spread of Emerald Ash Borer into uninfected areas has been done primarily through the movement of firewood.

Warning Camper! Did you Know... 

That all of Iowa, and certain areas of Colorado, Indiana, Illinois, Kansas Maryland, Michigan, Minnesota, Missouri, Ohio, Pennsylvania, Virginia, West Virginia, and Wisconsin are currently under a federal firewood transport quarantine established by the Animal and Plant Health Inspection Service (APHIS), U.S. Department of Agriculture to prevent the spread of emerald ash borer (EAB). It is felt that EAB may be resident in the wood and could be spread through firewood transport to un-infested areas. It is in direct violation of the USDA APHIS quarantine for you to bring firewood from a quarantined state or county into non quarantined areas.

The entire State of Iowa is quarantined for Emerald Ash Borer. Although it is not illegal to transport firewood within the state it is still strongly recommended that firewood should be obtained only within the county where it will be burned. It is important not move firewood from county to county or state to state to prevent the spread of forest pests.
Please help protect Iowa's forest resource by reporting illegal firewood by turning in this completed form: Report Illegal Firewood

New Law for Selling Firewood in Iowa began in 2011

Woodland Management Options

Forest inventory data estimates that Iowa's woodlands have over 52 million ash trees. Ash trees play an extremely important role in forest ecosystem function and health in Iowa. Many woodland owners have contacted the DNR with concerns about whether they should be harvesting ash before EAB arrives in the area.

Here are the current management recommendations:

  • Until EAB is found in the area, continue regular forest management and scheduled harvests. 
  • In stands where ash forms 20% or more of the basal area, reduce the ash component during regularly scheduled thinning or harvesting. 
  • When selecting ash trees to thin, first remove those that have low vigor and quality and maintain dominant and co-dominant ash trees with good form/health for future harvests. 
  • When replanting or direct seeding, promote species other than ash. The goal should not be to eliminate ash, but to try to keep ash to 10% or less of all regeneration. 
  • As always, contact your local district forester for assistance in developing a management plan for your woodlands.




What is Iowa Doing?

Emerald Ash Borer flecking example

Flecking from a woodpecker on a Ash tree. Tivon Feeley IDNR