Emerald Ash Borer Invasive Pests Invasive Insects

The emerald ash borer (Agrilus planipennis), is a destructive beetle native to Asia that is fast becoming a pest in the United States and Canada.  This invasive species has already destroyed tens of millions of trees since first being discovered in the Michigan in 2002.    The emerald ash borer is a splendid metallic green color and is described as beautiful as far as insects go.  But gardeners and nature lovers beware the emerald ash borer is every bit as destructive as it is beautiful; so much so that ash trees throughout North America could be extinct in the next few years.

 The adult emerald ash borer is not destructive to the ash tree itself; it is seen as more of a nuisance. Adult beetles eat the foliage of mature ash trees but do little damage during feeding.  The destruction of the tree occurs when an adult female emerald ash borer bores a hole in the trunk of an ash tree and lays up to 75 eggs deep within its bark.  Trees infested with beetle larvae can be spotted by a unique “D” shape that a female bores into a tree before depositing her eggs. 

 Once ash borer eggs hatch larvae emerge. They are voracious eaters tunneling their way through the inner bark of an ash tree leaving distinct “S” shaped patterns, scaring the wood. This process stops an ash tree’s ability to transport water and other nutrients throughout its root system thus killing most infected trees within two years.  It is hard to diagnosis an ash tree as infected until dieback starts occurring.  Over ½ of an infected tree’s branches will die off first.  The remaining canopy will often die off the second year after infestation. 

 Until scientists can stop the beetles’ massive destruction they have resorted to unusual measures to stop further destruction.  When a tree is found to be infested with beetle larvae they often destroy all ash trees within ½ mile of the infested tree hoping to eliminate the emerald ash borer from the area.  While many healthy trees are destroyed it might be the only way to save the entire species of ash trees.

 Since scientists first discovered the presence of the emerald ash borer in the United States almost 10 years ago the beetle’s range has spread to at least 10 other Midwestern and Northeastern states and two provinces in Canada.  Scientists aren’t quite sure how the emerald ash borer arrived in North America but they think that the insect arrived on a commercial freighter ship or a cargo airplane inside of a wooden cargo crate or some sort of wooden packing material.  Since its arrival in North America the emerald ash borer has destroyed over 25 million ash trees. 

 Scientists are educating the public, teaching homeowners what to be on the lookout for if they have ash trees on their properties, encouraging them to be vigilant if they suspect the presence of the emerald ash borer, by calling their local agricultural extensions.   Scientists have also quarantined infected regions by banning the cutting of firewood and banning the removal of ash wood from those regions. Emerald Ash Borer Beetle Quarantine exists in portions of Michigan, Illinois, Indiana, Ohio, Pennsylvania, Maryland, Virginia, West Virginia, Quebec, Ontario, Minnesota, New York, Kentucky, Wisconsin and Missouri. And the list is growing.

  Hikers and outdoorsmen need to be extra vigilant in recognizing the emerald ash borer to prevent spreading the insect to new regions.   Campers and other outdoorsmen need to be aware that individual states and counties are now placing bans on importing firewood across state or county lines.  For example some individual counties within the quarantined regions have posted a warning to all campers that they must only burn firewood purchased within the county and campers do need to have a receipt that their firewood was purchased within county limits.  Some states and counties are going as far as banning camp fires altogether until the emerald ash beetle infestation is under control.  Where campfires are permitted scientists urge campers to not take any firewood home with them but to burn it instead. 

 Spring is here and scientists encourage homeowners to inspect ash trees growing on their property for suspected infestations.  Homeowners should look for “S” shaped tunneling, canopy dieback or increased woodpecker activity.  Woodpeckers love to eat ash borer larvae.  Emerald ash borers will only infect ash trees.  If a homeowner suspects an infestation he should call his local agriculture extension immediately. 

 So far scientists do not have a cure or a treatment for the disease but research is being done.  If the emerald ash borer isn’t stopped in the next few years the future for the ash tree in North America may be grim.  For further information on the emerald ash borer please visit: www.aphis.usda.gov/ppq/ep/eab/quarantine.html.