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Emerald Ash Borer
Emerald Ash Borer

Emerald Ash Borer (Agrilus planipennis), or EAB as it’s commonly known, is a small, metallic-green, invasive wood-boring beetle native to east Asia that attacks and kills ash trees (fraxinus spp.). Adult beetles live on the outside of trees and feed on the leaves during the summer months, while the larvae feed on the living plant tissue, the phloem and cambium, underneath the bark. The tunneling and feeding activity of the larvae is what ultimately kills trees. EAB attacks trees of any size, age, or stage of health, and trees can die within two years of infestation.

Current Map of Iowa EAB Infestations

EAB was first discovered in North American near Detroit, Michigan in 2002, and has been found in numerous other states, as well as Canada, since then. It was discovered in Iowa in 2010 on in island in the Mississippi River near the town of New Albin. Since then, the beetle has moved westward through the state, and new infestations have been found on an ongoing basis. People are responsible for its spread, which is caused by the inadvertent movement of infested firewood, ash nursery stock, and other ash items. Early inventory data indicates that there are roughly 52 million woodland ash trees and 3.1 million community ash trees in Iowa. As ash is one of the most commonly planted street trees in the state, EAB will have a huge impact on the forest resources of cities and towns throughout.

NOTE: Iowa DNR does NOT recommend using imidacloprid drenching for the treatment of EAB. For more information about treatment, please refer to the Potential Side Effects of EAB Insecticides FAQ.


showing that eab is smaller than a penny

Adult Adult beetles are approximately 1/4-inch long and 1/8-inch wide and emerge from beneath the bark through D-shaped exit holes from May through mid-July. They are most active on warm, sunny days and spend much of their time feeding on ash leaves, which leads to the formation of harmless notches. Adults are able to fly between 1 and 4 miles, depending on wind speed and direction. The average lifespan of an adult is estimated to be about 6 weeks from the time of emergence.

Larvae (immature stage of EAB) After mating, female adults will lay 60-90 eggs in crevices of tree bark; these eggs hatch into the larvae that borrow through the live tissue and eventually kill the tree. Larvae are white and slightly flattened and have a pair of brown pincher-like appendages called urogomphi on their last abdominal segment. They vary in size but eventually grow to an average of 1.5 inches in length. Larvae burrow and feed in a distinctive S-shaped pattern, which is one of the easiest ways to identify whether a tree is infested.

EAB larvae

All true ash trees (fraxinus spp.) have opposite-branching and pinnately compound leaves with five or more leaflets. Seeds have two samaras and resemble miniature canoe paddles.

ash, opposite branching opposite branching ash tree leaves compound leaf quilted bark of ash trees quilted bark ash tree seeds seeds

Certified pesticide applicators in your area: Certified Pesticide Applicator Database (IDALS) Applicators with International Society of Arboriculture (ISA) certification: ISA Arborist Database

Ash trees are a common and important component of Iowa’s urban and community forests. Current inventories have found that ash species make up approximately 17% of total street tree canopy for the average Iowa community, with some communities seeing numbers over 50%. The damage caused by EAB will rival or surpass any forest pest that Iowa has seen in the past, and the costs associated with treatment and removal are high. However, with proper preparation and management practices landowners and community leaders can minimize the loss of resources and money that result.

For communities Adequate preparation includes consideration of the following questions:

  • Who will cut and haul away dead and dying trees?
  • Is there an accessible, secure site big enough to store and sort hundreds or even thousands of trees and the associated brush and chips?
  • How will the wood be disposed of or utilized?
  • Do we possess equipment capable of handling the size and quantity of trees needed to be removed?

Disposal costs can be reduced with advanced planning – Don't wait until EAB arrives to investigate options.

Certified pesticide applicators in your area: Certified Pesticide Applicator Database (IDALS) Applicators with International Society of Arboriculture (ISA) certification: ISA Arborist Database

Ash trees are a common and important component of Iowa’s urban and community forests. Current inventories have found that ash species make up approximately 17% of total street tree canopy for the average Iowa community, with some communities seeing numbers over 50%. The damage caused by EAB will rival or surpass any forest pest that Iowa has seen in the past, and the costs associated with treatment and removal are high. However, with proper preparation and management practices landowners and community leaders can minimize the loss of resources and money that result.

Disposal costs can be reduced with advanced planning – Don't wait until EAB arrives to investigate options.

For landowners Current recommendations are as follows:

  • 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 trees with good form and 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 it to 10% or less of all regeneration.
  • As always, contact your local district forester for assistance in developing a management plan.
Firewood
Do not move firewood sign

The spread of EAB into uninfected areas has been done primarily through the movement of firewood. Iowa is currently under federal firewood transport quarantine, which means that, although it is not illegal to transport firewood within the state or into other quarantined states, it is strongly recommended that firewood only be obtained from within the county where it will be burned. 

Additional states under quarantine include Colorado, Indiana, Illinois, Kansas, Maryland, Michigan, Minnesota, Missouri, Ohio, Pennsylvania, Virginia, West Virginia, and Wisconsin. Transport of firewood from a quarantined state to a non-quarantined state is illegal per USDA Animal and Plant Health Inspection Services (APHIS) protocol.

You can help protect Iowa’s forest resources by using the following form to report illegal firewood transport: Report Illegal Firewood


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