The symptoms and signs of an infested ash tree with emerald ash are similar to those symptoms that are caused by other pests and diseases. As an example, crown dieback can occur from emerald ash damage, but they can also be brought on by soil compaction, drought stress or verticillium wilt, to name a few. Because of this, it is imperative that a combination of a couple of symptoms is identified when trying to find out whether you truly do have emerald ash borer in your trees. If you see at least two of the symptoms listed below, you might have a severe problem.
Dieback of the outer and upper part of the crown will often begin after years of emerald ash feeding. Trees begin showing dead branches in the canopy area, starting toward the top. When larval feeds on the tree, it ends up disrupting the flow of nutrients and water into the upper part of the canopy, which results in leaf loss. Leaves at the top are discolored and thin.
Vertical splits are often the result of callus tissue developing around the galleries, which are often found beneath the splits.
If the trees are sick or stressed, they will attempt to grow out new branches and leaves wherever they are able. Trees could end up with new growth at the bottom of the tree and the trunk, often below the point where the larvae are feeding. Branches end up growing along the trunk just a few feet off the ground.
Woodpeckers will eat the emerald ash living underneath of the bark. This often occurs higher in the tree where the borers like to attack first. If there are a lot of the larvae living underneath of the bark, woodpeckers can end up damaging the tree and making it appear as if a large amount of bark has been stripped from the tree, which is referred to as flecking.
Larvae are often cream in color, slightly flat and have pincher appendages along the end part of their abdomens. By the time they are fully grown, they are about 1.5 inches in length. They are commonly found feeding beneath the bark of the tree. Once these beetles are adults, they are a metallic green in color and about the size of a piece of cooked rice. An adult beetle is flat on their back and their undersides are rounded.
Regardless of whether you are dealing with the start of an infestation or a full-blown infestation, you need someone who is trained to come out and get rid of these pests for you in a timely fashion to avoid damaging all of your other trees.