Emerald ash borer (EAB) is an insect that has caused serve damage throughout the Midwest. It sweeps through cities killing every Ash tree in its path. Often an infestation begins quietly with little indication of what is to come. Within 2-5 years it suddenly appears as if it came out of nowhere. Typically by the time a homeowner notices obvious signs and symptoms - EAB has been present for more than a year. Unfortunately, it is also typically too late to save the tree. So what are the options if you have Ash trees that you really care about? There are currently three primary management strategies.
The first option is to simply remove the Ash tree. If you know immediately that you are not willing to pay for treatments to prevent an EAB infestation then removal is a good option. Many cities are advising preemptive removal of Ash trees to reduce available hosts. Avoid waiting until the tree is dead and has become dangerous. Removal costs will typically be less for a live structurally sound tree than a dead brittle tree. Timing of removal is up to the homeowner to decide. Some people like to reap the benefits of their tree until it begins to decline, whereas others would rather not wait.
A second option is an insecticide treatment. There are many options as far as treatment types and chemicals on the market. Systemic treatment via trunk injections with the chemical Emamectin benzoate has proven to be the most effective. Treatment initiation is recommended if EAB has been detected within 15 miles of your residence. The Emamectin benzoate treatment in the spring typically provides at least 2 years of protection. A cost/benefit analysis can help in the decision making process as to if removal or treatment is the best option. An average 20'' diameter tree typically costs roughly $200 to treat. This would be $100 per year or $8.32 per month. If the tree provides greater value in cooling costs perhaps treatment is best. However, it must be noted that treatment is required indefinitely until EAB is eradicated from an area. Additionally, Injections should only be done by a trained professional to avoid damaging the tree.
The third option is a combination of the two with an emphasis on community management. By getting communities and/or neighborhoods to coalesce and create a management plan for EAB costs may be reduced and the neighborhood esthetic preserved. Weak, unhealthy, and undesirable trees in the community are removed while valuable Ash trees in the area are treated. This removes weak host plants and maintains the current esthetic and benefits of mature trees. Additionally, an arborist working with community or neighbor will often offer discounted rates for such large blocks of treatment. Consider talking with your neighbors about getting a community tree inventory to identify the quantity and quality of Ash trees in your community.
There are a number of options and considerations when deciding what to do about EAB when it finds your area. If you are lucky you don't have an Ash tree on your property to worry about. However, Ash is one of the most common tree species found in urban areas so chances are good that you may have to deal with this issue. Deciding on what management strategy is right for you will depend on the condition, location, and size of your tree(s) and how much you value the tree(s) in your landscape. Before making a decision I would always advise meeting with an ISA Certified Arborist to consult and get the opinion of a professional.