Before You Begin
Background Information and Frequently Asked Questions
Arrest That Pest! is designed to encourage responsible environmental decisions in young people by helping them understand the destructive behavior of the Emerald Ash Borer and other invasive species in their community. Before you begin, however, it is important to understand why education about invasive species is so important. Each year more than $137 billion is being spent in the United States to control about 900 invasive species and repair their damage. The environmental losses, such as the extinction of native plant and animal species and reduced biodiversity and natural beauty, are dramatic and permanent. Below you will find answers to some of the questions that are frequently asked about the Emerald Ash Borer.
Frequently Asked Questions About Emerald Ash Borer
Where did the Emerald Ash Borer (EAB) come from?
The natural range of the emerald ash borer (Agrilus planipennis) is eastern Russia, northern China, Japan, and Korea. Before June 2002, it had never been found in North America.
How did it get here?
Scientists can’t say for sure, but EAB probably arrived in solid wood packing material that originated somewhere in Asia. This would include wood used for crating, pallets, and stabilizing cargo in ships.
What do Emerald Ash Borers look like?
The adult beetle is dark metallic green in color, ½" long and 1/8" wide. When adults flare their wings, you can see their purple abdomen. The larvae are cream-colored grubs with flat bodies, bell-shaped segments, and wide heads.
What types of trees does the Emerald Ash Borer attack?
In North America, the beetle has only been found in ash trees. It will attack any size or species of ash in any location – large or small, urban or forest, healthy or stressed; among ash, the borer does not discriminate (EAB does not attack Mountain Ash - is not a true ash tree). In addition, ash trees have little or no resistance to EAB. Scientists have found that EAB adults are more attracted to stressed trees and that the larvae develop more rapidly in these trees, but even the healthiest trees have been killed when EAB population densities are high. To this point, natural enemies have had little impact on EAB.
What is the life cycle of EAB?
Recent research has shown that in heavily infested trees or in trees that are stressed, most EAB have a one year life cycle. In healthy trees that have only a few larvae, most EAB require two years to complete their development. Adult beetles begin emerging in mid to late May with peak emergence occurring during the month of June. The adult insects are most numerous in late June and early to mid July. Females begin laying eggs approximately two weeks after they emerge. The eggs hatch in one to two weeks and the tiny larvae bore through the bark. The larvae remain here for several weeks, usually from late July through October, feeding on the tissue that carries water and nutrients to the tree. Most EAB remain in small chambers underneath the outer bark over the winter. Pupation occurs in the spring, and new generations of adults emerge in May to begin the cycle all over again.
What happens to infested ash trees?
The distinctive "S" shaped tunnels excavated by feeding larvae destroy the water and nutrient conducting tissues under the bark. The tree literally starves to death in approximately 1 to 3 years.
What are the signs and symptoms of an ash tree infested with EAB?
The canopy of heavily infested trees will begin to die, usually near the top of the tree and progressing down the trunk. Sometimes ash trees produce epicormic sprouts or "water sprouts" on the trunk or large branches where EAB damage is heavy. Bark may crack over larval galleries. Adult beetles leave a characteristic "D" shaped exit hole in the bark, roughly 1/8" in diameter when they emerge in June. Woodpeckers often attack larvae, especially during the winter. Woodpecker holes are larger and easier to see than the D-shaped holes left by EAB. Several infestations have been discovered because people noticed woodpecker damage in trees.
How is the pest spread?
EAB adults do not fly very fast or very far, usually moving no further than a ½ mile from where they emerge. The primary movement of the borer is through infested ash wood products and debris that is transported by people.
Where can I get more information about the Emerald Ash Borer?
For more information on Emerald Ash Borer in Indiana, please visit:
Purdue Extension: (888) EXT INFO (888-398-4636)