Figure 2—S-shaped tunnels, made by EAB larvae, 

riddle infested ash trees.

The emerald ash borer (EAB) is a very small but 

very destructive beetle. Metallic green in color, 

its slender body measures 1/2-inch long and 1/8-inch 

wide. The average adult beetle can fit easily on 

a penny.

Native to China and eastern Asia, the EAB probably 

arrived in North America hidden in wood packing 

materials commonly used to ship consumer goods, 

auto parts, and other such products. Although no one 

can say for certain when the EAB arrived in southeastern Michigan, the scientific community now believes 

the beetle may have been present for up to 12 years 

before it was detected, based on its widespread distribution and destruction. The U.S. Department of 

Agriculture (USDA) officially identified the EAB in the 

summer of 2002.

This beetle is responsible for the death or decline 

of tens of millions ash trees. At press time (June 

2009), EABs have been detected in 13 States (Illinois, 

Indiana, Kentucky, Maryland, Michigan, Minnesota, 

Missouri, New York, Ohio, Pennsylvania, Virginia, 

West Virginia, and Wisconsin) and parts of Canada.

Signs and Symptoms of EAB

It is extremely difficult to determine whether an ash 

tree is or is not infested with the EAB because tree 

decline is usually gradual. Early symptoms of an 

infestation might include dead branches near the 

top of a tree or wild, leafy shoots growing out from 

its lower trunk. D-shaped exit holes and bark splits 

exposing S-shaped tunnels are significant signs of the 

EAB. Woodpecker activity might also indicate the 

presence of EABs.

If a tree is infested with the EAB, tree removal is 

the most effective way to eliminate these exotic pests 

and prevent the species’ further spread. Considering 

the most current science, USDA's Animal and Plant 

Health Inspection Service (APHIS) recommends felling infested trees and properly disposing of the wood.

Humans Contribute to the Spread of 

the EAB

In terms of the range and extent of EAB infestation in 

North America, human behavior is a particularly significant factor. People unknowingly contribute to the 

artificial spread of the EAB by carrying out activities 

that are part of everyday living and commerce. The 

movement of common ash tree products—such as 

firewood, nursery stock, green lumber, branches, logs, 

and chips—has been a primary means of advancing 

the beetle’s spread.

EAB Quarantines in the United States

To prevent additional artificial spread of the EAB, 

USDA has established quarantines to prohibit the 

movement of ash materials and hardwood firewood 

out of States where EABs are known to exist. Today, 

the entire States of Illinois, Indiana, and Ohio, together with the Lower Peninsula of Michigan, are quarantined. USDA quarantines also exist in select areas of 

Kentucky, Maryland, Minnesota, Missouri, New York, 

Pennsylvania, Virginia, West Virginia, Wisconsin, and 

the Upper Peninsula of Michigan.

The movement of ash material and firewood intrastate (within a given State) is also prohibited under 

State government quarantines. Currently, State quarantines exist in all of the above-mentioned States.

Because new EAB infestations are periodically 

discovered, the areas under quarantine also change. 

Therefore, to avoid penalties, homeowners and businesses should check with their State department of 

agriculture for the latest information regarding EAB 

quarantines prior to transporting any ash materials or 

firewood.

Scientifically Speaking

Entomologists from the United States and Canada 

have been studying the EAB continually to learn more 

about its biology and behavior. Since the beetle had 

never been found anywhere in North America prior to 

2002, information about the EAB is regularly updated.

Scientists now know that, in a temperate climate, 

the beetles can develop from eggs to adults in as little 

as 1 year. From May to August, adults emerge from 

overwintering sites under bark and mate. Females lay 

eggs in bark crevices, and the eggs hatch in about 10 

days. The eggs develop into wormlike larvae, which 

tunnel under the bark to feed and grow throughout 

the fall. It is this tunneling and feeding that eventually kills the tree. Larvae lay dormant during the winter and emerge from trees in May as adults, leaving a 

unique D-shaped exit hole.

Here are some key discoveries scientists have 

made about the EAB:

n On this continent, the EAB attacks only ash trees 

(Fraxinus spp.), and all the ash species—including 

green, white, black, and blue—are at risk. The 

mountain ash (Sorbus spp.), is not a true ash and, 

therefore, is not threatened by EABs.

n EAB adults are strong fliers, yet most only fly short 

distances (about 1/2 mile). However, under certain 

conditions, individual beetles are capable of flying 

up to several miles to infest new trees.

n Several natural enemies have been discovered 

attacking EAB larvae in North America, including 

woodpeckers and at least two species of parasitic 

insects. Unfortunately, these enemies have not 

effectively prevented trees from dying or substantially slowed the spread of the pest.

Figure 1—The adult EAB, an exotic wood-boring 

beetle, attacks ash trees exclusively.

Figure 3—The D-shaped exit 

hole is a unique signature of 

the EAB.

Figure 4—Epicormic shoots 

are a telltale sign of a tree 

under stress.

n An EAB infestation is always fatal to ash trees. 

Infested trees decline from the top down and will 

be dead in 1 to 3 years, even if the trees were 

healthy before being attacked by the EAB. Stressed 

or damaged trees appear to attract the beetles.

n Cut and stacked ash wood more than 1 year old 

can harbor viable EAB larvae and continue to pose 

a risk for the pest’s artificial spread.

Ash Tree Treatments

Because research is ongoing, and pesticide regulations 

differ from State to State, homeowners should contact 

their State department of agriculture or local extension 

office for current guidelines regarding pesticide use for 

EAB-infested trees.

Pesticides can serve as a control measure for the 

EAB, but they are not a cure. 

Homeowners with individual, high-value ash 

trees can buy federally-approved insecticides at retail 

outlets or have their trees treated by State-certified 

pesticide applicators. Options include systemic and 

topical insecticides. These compounds will need to be 

applied on a regular basis, possibly several times within one growing season, and even then might not completely prevent the EAB from attacking an ash tree. 

In EAB-infested areas, even treated trees are likely to 

succumb to continued attacks from the pest as beetle 

populations increase. 

What You Can Do To Stop the Spread of 

the EAB

Detecting, controlling, and preventing the human 

spread of the EAB is a huge undertaking. Cooperation 

among Federal and State government agencies, municipalities, universities, the green industry, and the public is essential to minimize the impacts of this pest.

Here are some things you can do now to support 

the cooperative program and contribute to safeguarding the ash resource in the United States.
The U.S. Department of Agriculture (USDA) prohibits discrimination 

in all its programs and activities on the basis of race, color, national 

origin, age, disability, and where applicable, sex, marital status, 

familial status, parental status, religion, sexual orientation, genetic 

information, political beliefs, reprisal, or because all or part of an 

individual’s income is derived from any public assistance program. 

(Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 720–2600 (voice and TDD). 

To file a complaint of discrimination, write to USDA, Director, Office 

of Civil Rights, 1400 Independence Avenue, S.W., Washington, 

D.C. 20250–9410, or call (800) 795–3272 (voice) or (202) 720–6382 

(TDD). USDA is an equal opportunity provider and employer.

This publication reports research involving pesticides. All uses of 

pesticides must be registered by appropriate State and/or Federal 

agencies before they can be recommended.

 

CAUTION: Pesticides can be injurious to humans, domestic animals, desirable plants, and fish or other wildlife—if they are not 

handled or applied properly. Use all pesticides selectively and 

carefully. Follow recommended practices for the disposal of surplus pesticides and pesticide 

Cover photo: Bark’s-eye view of the EAB, a foreign insect that 

attacks all species of ash trees except the mountain ash, which is 

not a true ash.

Photo credits: The cover photograph and figure 10 were taken 

by APHIS employee Dr. James E. Zablotny. APHIS gratefully 

acknowledges the cooperation of Michigan State University’s David 

Cappaert, who supplied the images used in figures 1 and 5; these 

photographs are reproduced by permission. The images in figures 

2, 3, and 4 were supplied by APHIS employees David R. McKay, 

Brian Sullivan, and James W. Smith, respectively. The images 

in figures 6-9 were taken by Paul Wray (Iowa State University; 

reproduced from the Bugwood.org Web site), Robin Usborne 

(Michigan State University), Diane Brown-Rytlewski (Michigan State 

University), and Keith Kanoti (Maine Forest Service; reproduced 

from the Bugwood.org Web site), respectively. 

Web sites: http://www.aphis.usda.gov

 http://www.na.fs.fed.us/fhp/eab

 http://www.emeraldashborer.info

Revised December 2008

Slightly Revised June 2009

United States Department of Agriculture

Animal and Plant Health Inspection Service

Program Aid No. 1769

Emerald 

Ash Borer

The Green Menace

Figure 10—The female beetle lays eggs in bark crevices 

of ash trees.

Figure 5—EAB larvae can be transported to new 

locations while hidden under the bark of firewood.

Figure 9—In older trees, ash 

bark displays diamond-shaped 

patterns.

Figure 7—Ash tree branches are 

directly across from each other, 

almost as if you were looking in 

a mirror. This is called opposite 

branching.

Figure 8—Ash trees have 

compound leaves, composed 

of 5 to 11 leaflets.

Figure 6—Ash seeds are oar-shaped and can be found in 

clusters; however, not all ash trees reproduce seeds.

n Don’t move firewood. Humans unknowingly 

contribute to the spread of the EAB when they 

move firewood. EAB larvae can survive hidden 

under the bark of firewood. Play it safe: Don’t 

move any firewood, and you won’t move any

beetles. Buy local, burn local.

n Visually inspect your trees. Early detection is a 

key factor. If trees display any sign or symptom of 

EAB infestation, contact your State agriculture agency.

n Spread the word. Talk to your neighbors, friends, 

and coworkers about the EAB and what they should 

look for on their trees. 

n Know State and Federal regulations. Make sure 

you understand the regulations that govern your own 

State and those States and Provinces you might visit.

n Ask questions. If you receive ash nursery stock or 

firewood, know its point of origin and your supplier. 

EAB larvae could be hiding under the bark. 

Ash Tree Identification

Ash trees are used extensively in residential and commercial landscapes and are found naturally in woodlots, along creekbeds, and in low-lying wetlands. In 

the United States, ash trees are found from coast to 

coast and represent about 2 percent of the total leaf 

cover. Because the EAB attacks all species of ash, it is

important to be able to tell ash trees from other hardwoods. 

The following photos illustrate some characteristics of ash trees.

State EAB Hotlines

Call if you think you might have the EAB in your tree, 

have questions about the program or quarantines, or 

want to report illegal ash wood or firewood movement.

Alabama 800-642-7761 

Arkansas 501-324-5258 

Delaware 800-282-8685 

Illinois 800-641-3934 

Indiana 866-663-9684 

Iowa 515-725-1470 

Maine 800-367-0223 

Maryland 800-342-2507 

Michigan 866-325-0023 

Minnesota 888-545-6684 

Missouri 866-716-9974

Kansas 785-862-2180

Nebraska 402-471-2394

Nevada 775-688-1180

New Hampshire 603-271-7384

New York 866-640-0652

North Dakota 701-328-4765

Ohio 888-644-6322

Pennsylvania 866-253-7189

South Dakota 800-275-4954

Texas 936-639-8170

Vermont 802-241-3544

Virginia 804-786-3515

West Virginia 304-558-2212

Wisconsin 800-462-2803

National EAB Hotline 866-322-4512