Image Credit: the USDA.gov website (public domain)
Image Credit: Ohio Dept of Agriculture website (public domain)
The small Emerald Ash Borer Beetle has a justifiably bad reputation for destruction, radically deforesting neighborhoods in just a few years.
The Emerald Ash Borer is one in a line of destructive tree beetles in North America. As recently as June 2002, the beetle was identified in Windsor, Ontario and in the southeast portion of the state of Michigan. In less than a decade, it became a well-known problem insect. It is native to Asia, found locally in parts of Japan, the Koreas, China, Mongolia, and Russia. A few beetles likely hitched a ride on cargo during shipping and that is when trouble on the North American continent began.
The Emerald Ash Borer is a highly invasive species, capable of populating a large area in a very short period of time. It is also highly recognizable thanks to its metallic green coloring. The insect makes no distinction between wild areas and landscaped growth, attacking the leaves and bark of the Ash tree species wherever it happens to grow.
Emerald Ash Borers (EABs) are related to native species of North American tree borers. They all share some similarities in how they feed, mate, and otherwise operate in adulthood. Adults appear in the late spring months and into early August. One generation lives per year, but it can wreak havoc in little time if left unchecked. The adults that emerge from the tree trunks leave a small, visible "D" shaped hole in the bark of the Ash tree. They proceed to feed off of the tree's foliage before mating several weeks later.
Upon mating, the female beetle can lay upwards of 50 to 100 eggs on the surface of the tree, allowing the larvae to easily begin boring into the tree once they are born. Larvae dig into the area just under the bark and continue boring tunnels while feeding on the sapwood inside the tree. This draining of tree fluids continues from the summer season into the fall. The death of the tree is caused by dehydration and starvation. The small tunnels block or destroy the xylem in the tree trunk which allows water to move up the tree. Ash trees that are infected and impaired will have seasons where only a few branch cluster grow leaves, while other parts are bare. Suffering Ash trees will try to grow new shoots from the base of their trunks in an effort to stay alive.
Ash trees offer a tremendous amount of natural beauty to neighborhoods. They are an important part of the temperate forest ecosystem and are harvested for use. Targeting the larvae is instrumental in stopping the spread of the Emerald Ash Borer, and the only known solution to stop them is the removal and destruction of all infected trees. This usually results in an entire neighborhood's treescape changing because Ash trees were popular decades ago in urban and suburban planning. In many places, this species alone was planted for miles. Now block after block loses shade and character in an effort to stem infestations.
Quarantines of known infected areas and trees is currently ongoing throughout many states and provinces. It is thought that the presence of Woodpeckers might be an indication of infestation because Woodpeckers seem enjoy hunting the larvae under the bark. At this time, the EAB feeds only on Ash trees (known as Fraxinus spp.). If you suspect your Ash tree is affected, contact your local government to have the village/city look at your tree.
Scientific Name: Agrilus planipennis
Size (Adult; Length): 10mm to 13mm (0.39in to 0.51in)
Note: An insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed above as they are driven by environmental factors (such as climate change), available food supplies and mating patterns. Grayed-out selections indicate that the subject in question has not been reported in that particular territory. U.S. states and Canadian provinces / territories are clickable to their respective bug listings.
Antennae: Beetles have a pair of antennae on the head used as sensors.
Head: The head is home to the insect's eyes, antennae, and mandibles (jaws).
Thorax: Holds the three pairs of legs as well as vital internal organs.
Elytron: One of two wing cases on a Beetle that protects its wings (plural: elytra).
Wings: Appendages used for flying and kept under the elytra until needed.
Abdomen: Houses organs related to circulation, reproduction, and excretion.
Legs: Beetles have three pairs of legs located at the thorax, numbering six legs in all.