WHAT IS THE EMERALD ASH BORER?
Agrilus planipennis Fairmaire, a beetle native to Asia, was first detected in Michigan in 2002. Evidence suggests that the beetle was established in Michigan for a number of years prior to its discovery. Emerald ash borer has since been detected in Ohio, Indiana, Virginia, Maryland, and Ontario, Canada. In addition to spreading by natural means, emerald ash borer can be transported to new areas in infested firewood, timber and nursery stock. The beetle is responsible for the loss of more than 7 million ash trees in Michigan alone.
In North America, emerald ash borer is known to infest all species of ash (Fraxinus spp.). Ash can be recognized by the presence of compound leaves which are arranged opposite of one another on the branches. Eggs are laid between layers of bark and in bark crevices. Larvae hatch in about one week and bore into the tree where they feed on the inner bark and stem, creating “S”-shaped galleries. The larvae go through three feeding stages, and then excavate a pupal chamber in the fall, where they will overwinter as prepupae. Pupation occurs in late spring, and adults begin to emerge through “D”-shaped exit holes in May and early June. Adults will remain active until the end of summer.
New infestations are difficult to detect as damage to the tree may not be apparent for up to three years. Signs of older infestation can include branch dieback in the upper crown, excessive epicormic branching on the tree trunk, vertical bark slips and woodpecker damage. Ash may also be stressed by drought, diseases such as ash yellows and by native insects like the redheaded ash borer, Neoclytus acuminatus, (Fabricius) which creates a round emergence hole. It is important to note that exotic pests such as the emerald ash borer can be spread when infested firewood is transported to new areas. To protect our forests and trees and stop the movement of exotic pests, use local firewood, do not bring firewood from home and if you have already transported firewood, do not take it home, do not leave it, burn it! Do Not Move Firewood!