Looking at the trees clustered below my home, I have four big trees that have died this year.
We have had a wonderful growing season, so I wondered, “Why”?
When my forestry friend came for a visit, I asked if he had noticed the same problem. Of course, he knew exactly what was wrong and identified the trees that were lost as Ash. We have two kinds of Ash growing in our area, Green Ash, Fraxinus pennsylvanica, and White Ash, Fraxinus Americana.
The reason for the demise of our native tree is the Emerald Ash Borer (EAB), Agrilus planipennis; they attack only ash trees. This insect was first discovered in the United States in Michigan in 2002 and is believed to have originated on wood packing material from Asia. Yes, Asia again; we can already thank them for Japanese beetles, Asian lady bugs, Asian Long-horned Beetles and our most recent scare, Asian Giant Hornets.
Since discovery, this destructive insect has been found in numerous states, including Tennessee. Typically, the emerald ash borer beetles can kill an ash tree within three years of the initial infestation. The emerald ash borer is a metallic green beetle that bores into ash trees feeding on tissues beneath the bark, ultimately killing the tree. EAB is now found in many of the Midwestern and Eastern states and has already killed tens of millions of ash trees.
The larvae (the immature stage) feed on the inner bark of ash trees, disrupting the tree’s ability to transport water and nutrients. This disruption of food and water within the tree in effect girdles it and causes the tree death. Both healthy and unhealthy trees can be attacked.
Adults are dark green, one-half inch in length and one-eighth inch wide, and fly only from April until September, depending on the climate of the area. In Tennessee, most EAB adults fly in May and June. Larvae spend the rest of the year beneath the bark of ash trees. When they emerge as adults, they leave D-shaped holes in the bark about one-eighth inch wide.
Ash trees are an important forest tree in our area. White ash wood is used for handles. It is the standard for shovels, spades, hoes, and rakes. It can also be found in furniture, especially the bent parts of chairs. Sporting equipment such as oars and baseball bats use this smooth fine-grained wood. It is also a good fire wood.
What can we do to stop the spread? We are encouraged to cut down dead and dying ash trees and chip, burn, or bury the wood on the site, in accordance with all local regulations, to reduce the chance of other trees being attacked. This is a big problem and sounds like a lot of work.
The NCDA&CS has issued a statewide quarantine to prevent the human-facilitated movement of EAB to new areas. The Emerald Ash bore is pretty, but we will probably never see it. We will only see the results — dead trees and the larva or the D-shaped holes left when it escapes to another tree.
Gayle Fisher is a master gardener for the state of Tennessee, as well as an accredited National Flower Show judge. A student consultant for landscape design, she has served as an officer in District IV Tennessee Federation of Garden Clubs and is a member of the American Horticultural Society. She can be reached at email@example.com