ENTFACT-453: Emerald Ash Borer (EAB) FAQs for Kentuckians  |  Download PDF

by Lee Townsend, Extension Entomologist
Lynne Rieske-Kinney, Professor, Forest Entomologist
University of Kentucky College of Agriculture 

This factsheet has been developed to provide information on the status of the emerald ash borer in Kentucky and some general information about the insect as it relates to spread and management. 

EAB Symbol

What is the status of the emerald ash borer in Kentucky?
The first infestations of the EAB were confirmed in May 2009 from sites in Jessamine and Shelby counties. Visit the Kentucky EAB site for the latest information. The first infestations of the EAB were confirmed in May 2009 from sites in Jessamine and Shelby counties. Visit the Kentucky EAB site for the latest information.

What makes an EAB infestation "official"?
The initial confirmation of EAB in a county must be based on the collection of a life stage of the insect– usually a larva or an adult. Larvae or adults collected from ash wood should be preserved in alcohol. Specimens are sent to the Animal Plant Health Inspection Service for confirmation before the insect is considered to be officially present. An exit hole or larval gallery in wood is not enough to make a positive identification for a new county record. 

What happens after an identification is confirmed?
The county will be placed under quarantine to prevent movement of infested articles and a survey will begin to determine the extent of the infestation. A management plan will be developed after the extent of the infestation and the density of ash in the area has been determined. 

On June 24, 2009, a quarantine was issued to include Boone, Bourbon, Campbell, Carroll, Fayette, Franklin, Gallatin, Grant, Harrison, Henry, Jefferson, Jessamine, Kenton, Oldham, Owen, Pendleton, Scott, Shelby, Trimble and Woodford counties. The quarantined area includes counties with confirmed infestations, those close to the infestations, and counties with a high density of ash trees. 

What does a quarantine accomplish?
The quarantine prohibits “regulated articles” from being moved outside the quarantine area without a certificate or limited permit except under certain conditions. A regulated article may be moved by the U.S. Department of Agriculture or the Kentucky Department of Agriculture for experimental or scientific purposes; may be moved in an enclosed vehicle or completely covered to prevent access by the emerald ash borer (through Sept. 30); may be moved directly through the quarantined area without stopping except for traffic conditions and refueling; may be moved if it is stored, packed or handled at locations that do not pose a risk of infestation; and may be moved if it has not been combined or commingled with other articles. 

"Regulated articles" are defined as the emerald ash borer, hardwood firewood, ash nursery stock, green ash lumber, other ash material, and any other materials that present a threat of artificial spread of the emerald ash borer. Regulated articles that have not been treated can be moved out of the quarantine area during the non-flight season (October thru March) with a limited permit. Both the shipper and receiver must have compliance agreements and the processing mill must process the materials by April 1. 

The EAB is in Kentucky to stay and its distribution in the state will continue to expand. A sound plan for living with it has been developed based upon research findings and experiences from older infestations. The challenge is to do everything we can to make the plan work and learn to manage the EAB. 

What trees does the EAB attack?
All species of ash (Fraxinus) in landscapes, forests, and woodlots in eastern North America are susceptible to attack by the emerald ash borer. Females may prefer to lay eggs on stressed trees but healthy ones also can be infested. Host size does not appear to be a constraint either, larval galleries have been found in trees or branches as small as 1 inch in diameter. 

EAB Damage: Under BarkEAB Damage: Under Bark

What does the EAB do to ash trees?
As they feed under the bark, EAB larvae destroy the tree’s water and nutrient conducting tissue. This reduces water and nutrient flow to the canopy and causes thinning above infested portions of the trunk and major branches. Dieback in heavily infested trees usually starts at the top with one-third to one-half of the branches dying in one year; most of the canopy will die within 2 years of the first appearance of symptoms. 

EAB: Exit Holes

What are signs of an EAB infestation?
The following general characteristics may be caused by EAB, other borers, stress, or physical injury:

- Thinning of canopy
- D-shaped 1/8" exit holes in the bark
- Serpentine-shaped tunnels under bark
- Young sprout growth at base of tree
- Woodpecker activity
- Vertical splits in bark 

How do infestations spread?
Normal flight spread of the EAB is between one-half to two miles a year so natural spread tends to be relatively slow. Unfortunately, movement of infested ash wood can result in jumps of hundreds of miles. Firewood has been a major means of transporting EAB, especially by hunters and campers. Slowing the spread can buy time to develop and implement management plans based on ash components of wooded areas and to take advantage of strategies that might be developed through current research. 

EAB AdultEAB Adult

Is the EAB easy to recognize?
Adults are distinctive dark metallic green beetles that are about 1/2 long and about 1/8 inch wide. They may be found resting or feeding on ash leaves during May and June. They emerge through distinct D-shaped holes in the bark. The larvae may be found tunneling under bark from July thru October. Fortunately, they are relatively easy to distinguish from native ash borers. 

Do insects other than the EAB live in ash?
Yes, the larvae of several beetles and moths can be found in forest and landscape ash throughout the state. The redheaded ash borer (a round-headed wood borer) and the ash borer (a caterpillar) are most common. Do not hesitate to bring any specimens from ash to your county extension office for identification. Private individuals are often the first to notice a new organism in an area and the EAB is too important to overlook. 

Should I begin to use insecticides to protect my ash trees from the EAB?
Treatment is an individual decision based on specific conditions. However, preventive insecticide applications generally are not recommended if known infestations are not within 15 miles of your location. If there is no quarantine for your county, identify ash trees on your property and keep them as healthy as possible through proper fertilization and watering. Watch trees closely for signs of EAB infestations. Stay informed about the situation in your area. 

Are insecticide applications worthwhile if nearby infestations are discovered?
Most insecticides currently registered for EAB control must be applied every year. Treatments may be worthwhile to protect very valuable trees or to keep individual trees alive until non-susceptible replacement trees are large enough to provide satisfactory shade. Detailed information on control alternatives is available at: http://pest.ca.uky.edu/EXT/EAB/EABcontrol.pdf 

EAB LarvaEAB Larva

What is the life cycle of this borer?
The EAB can have a one– or two-year life cycle, development time decreases and the number of borer larvae per tree increases. In Michigan adults begin emerging in mid to late May with peak emergence in late June. Females usually begin laying eggs about 2 weeks after emergence. 

Eggs hatch in 1-2 weeks, and the tiny larvae bore through the bark and into the cambium - the area between the bark and wood where nutrient levels are high. 

The larvae feed under the bark for several weeks, usually from late July or early August through October. The larvae typically pass through four stages, eventually reaching a size of roughly 1 to 1.25 inches long. Most EAB larvae spend the winter in small chambers in the outer bark or in the outer inch of wood. Pupation occurs in spring and the new generation of adults emerges in May or early June, to begin the cycle again. 

Who do I call to get more information on the EAB or to report an infested tree?
An Emerald Ash Borer Hotline 866– 322-4512 has been established by the Animal and Plant Health Inspection Service (APHIS), US Department of Agriculture. Collected information will be passed to the appropriate office for follow-up. You also can contact your local UK Cooperative Extension office or the Office of the State Entomologist (859) 257-5838. 

What steps are being taken in Kentucky to deal with the EAB?
Survey and monitoring programs have been implemented in Kentucky for early detection of EAB. A vigorous educational program has been implemented to inform the media and to raise public awareness. 


Issued: 7/07
Revised: 9/09

CAUTION! Pesticide recommendations in this publication are registered for use in Kentucky, USA ONLY! The use of some products may not be legal in your state or country. Please check with your local county agent or regulatory official before using any pesticide mentioned in this publication. 


Adapted from a fact sheet developed by Dr. Deborah McCullough and Robin Usborne, Michigan State University Extension, May 2007.  http://www.emeraldashborer.info/faq.cfm#6