The Emerald Ash Borer (EAB), a tiny green beetle, is killing millions of native ash trees across the country creating headaches to municipal foresters. This little creature is causing cities to spend thousands of dollars to protect the public from hazards and to save their urban forest from declining. Who knew such a small creature could cause a big problem in our communities.
What is the Emerald Ash Borer? This beetle, native to Asia, is only a shocking half an inch long with a green metallic color as an adult. During the pest’s larva cycle, it feeds in a part of a tree called the phloem, just under the bark of an ash tree. This part of the tree transports all the nutrients needed for a tree to survive, therefore EAB causes extreme damage to the tree. The larva causes damage by eating the phloem, leaving channels called galleries, in result restricting the tree’s ability to transport nutrients and eventually killing the tree.
This pest surprisingly is a very picky eater. It only infests in one native tree species called ash trees. Here in Illinois, this includes four native ash trees: green ash, blue ash, black ash, and white ash. Does your back yard host a species extremely susceptible to EAB? We can not answer that question without knowing how to identify an ash species. The easiest identification characteristic of this tree is a distinctive bark pattern. The bark has diamond shaped furrows forming ‘X’ patterns which stands out from most other tree species.
Another good way to identify an ash tree is the look at the branching and the leaves. The leaves are compound leaves that have five to eleven leaflets with a terminal leaflet pointing outward from the tip of the leaf. The growth habit of this tree grows opposite bud and branch formation, each branch or leaf is paired with another directly across from it.
Ash wood is popular to be used for firewood because it burns so well. This beetle can fly but it spreads to new areas most commonly by people. We spread the beetle by transporting ash firewood that may contain the beetle or larva. In a sense, we are the main issue to contributing to deforestation of our native ash trees.
In order to find if an ash tree has been infested by EAB there are signs and symptoms you need to consider. The most common symptoms are crown die-back, new growth around base of tree, and woodpecker damage seen on bark. Remember, those galleries restricted the movement of nutrients, therefore nutrients can not reach the top so the tree reacts by producing new growth at the base and die back in the crown. Woodpeckers like to consume the EAB larva, in result woodpecker damage to the trunk and branches of the tree. Signs for EAB are ‘D’ shaped holes. These holes are small and hard to find, however, they are exit holes from new EAB beetles and would indicate infestation of EAB is a positive occurrence.
Now you have some basic background knowledge about Emerald Ash Borer, how is it affecting your community? Trees can offer many benefits to a neighborhood, however, without any management they can cause hazards to the public and the total canopy can be reduced. In the Midwest, typically an urban forest has ash trees that make up for roughly ten to forty percent of the total canopy. Imagine, you are driving down a street in a community that has been infested by EAB, and each block has ten trees. Each block has one to four trees that hold deadwood ready to fall and cause damage to anything within its target zone. Now think of the whole township, there are many targets that are at risk of getting damaged. Also, while keeping that in mind, imagine the number of trees that are no longer providing shade, value to a piece of property, or cooling the environment around them. Not only are there hazards but the environment around the city is getting effected. With all the issues it is causing public works departments to spend thousands of dollars. For example, Fort Wayne, Indiana, in 2012, the city budgeted for $900,000 annually for tree removal, chemical treatment, and replanting all relating to the infestation of EAB to the city. In a whole, most people don’t realize how big of an issue this can become and it can put a negative effect in your community.
Although Emerald Ash Borer is a very destructive pest, homeowners and cities can plan to beat them. Preparation and management to an urban forest whether EAB has reached town yet or not can be effective to protect the local native ash trees depending on a budget. There are insecticides that can kill the larva; the most poplar insecticide is named Tree-age which has an active ingredient of Emamectin benzoate. Chemical treatments work the best before the pest infests the tree but can still save a tree that has a low number of pests. A cities management plan may differ depending on financing. Management includes insecticide treatments, removal, and planting new trees of a different species. A city with an aggressive management plan will choose particular trees they will treat for many years while the rest of the ash trees will be removed and replaced by a new tree of a different species.
Emerald Ash Borer continues to spread around the country destroying forests forcing us to spend thousands of dollars. It is important to me as a student learning to protect our trees and tree care professionals to educate the public about the destructive pest in effort to diminish and stop the destruction of our native ash trees.
If you think you have EAB or an ash tree at your home, click on the links below to read more information and to find your local certified arborist.
Photo credits: Google
My name is Zach Woodbury and I am a senior majoring in Agriculture Science with an emphasis in Forestry and a minor in Computer Science. I am happy to be president of the WIU Forestry Club and a member of the Horticulture Club. I have high hopes to pursue a career in the tree care industry as a certified arborist. I grew up in a very rural town named Lee in Northern Illinois. Although I come from a rural community, I learned at a young age to be a dedicated outdoorsman fishing and hunting, spending most of my time admiring nature. Later I would grow a passion to care for our biggest and most important organism, trees.