About the Emerald Ash Borer

Emerald Ash Borer is a deadly threat to ash trees, killing host trees within three to five years of infestation. The pest belongs to a group of insects known as the metallic wood-boring beetles. Adults are dark metallic green in color, 1/2 inch in length and 1/8 inch wide, and fly only from early May until September. Larvae spend the rest of the year developing beneath the bark of ash trees, and when they emerge as adults, leave D-shaped exit holes in the bark about 1/8 inch wide.

Note the characteristic D-shaped exit hole. Once they become adult beetles, they crawl through the bark, leaving these exit holes.	EAB larvae choke the Ash tree by eating through the cambium layer just under the bark.

The pest is difficult to detect in its first year of infestation, as it first infests the tops of ash trees and works its way down. Infested ash trees are essentially choked to death by larvae feeding on the cambium layer -- the live tissue just beneath the bark responsible for transporting nutrients throughout the tree. Signs of EAB include dieback at the tops of ash trees, D-shaped exit holes, S-shaped larval galleries, epicormic sprouts, woodpecker damage, and bark splits.

Research has shown that the natural spread of the pest is less than one-half mile per year. However, EAB can be easily, yet unknowingly spread through the movement of infested ash material such as logs, nursery stock, firewood, etc. The majority of infestations were introduced through the artificial spread of this insect.

Many states and provinces are now aggressively spraying ash trees to stop the spread of this deadly pest.