Emerald Ash Borer

Emerald ash borer

Emerald ash borer, native to Asia, was first discovered is Michigan in 2002, and has since killed millions of ash trees in neighboring states.  On its own, emerald ash borer is suspected to travel only up to 15 miles a year; however, due to transporting firewood and cargo, humans have been determined to be the main reason for the rapid spread of the emerald ash borer and ultimately the devastation described above. Emerald ash borer was found in August of 2008 within Washington and Ozaukee counties. Since its initial discovery, it has also been found in Milwaukee County, Oak Creek, Franklin, and Western Wisconsin within the county of Vernon. Emerald ash borer has now been found in the city of Milwaukee. In a press conference, Tom Barrett Mayor of Milwaukee, met with the public works Commissioner, and the Milwaukee Forestry Services Manager to declare a state of emergency concerning an imminent city wide Emerald Ash Borer propelled by drought. Tom Barrett said, “treat them or remove and replace them with resistent-type shade trees before they become infested with emerald ash borer.”

Affected Trees: all known ash spiecies

Noticeable Signs

Common signs of emerald ash borer tend to show:

  • die back within the top 1/3rd of the canopy as well as suckering along the trunk can be a sign of an emerald ash borer infestation. 30 to 50% of canopy dieback can be expected within two years of infestation.
  • S-shaped larvae galleries can range from 4-20 inches in length, expanding in width as the Larvae grow in size. Look for small vertical splits in the bark along twigs and trunk. D-shaped exit holes, approximately 1/8th inch in diameter, will appear on the trunk after first year of infestation.
  • a bronze to golden green body and a metallic emerald green wing cover can identify an adult borer. Their abdomen is metallic purplish to red.
  • emerald ash borers will range anywhere from ¼ inch to ½ inch in length. After their larvae state, they remain in the pupal chamber until may to mid august and then feed and reproduce depositing pre-pupa larvae to overwinter in the bark or outer sapwood.

Emerald Ash Borer Treatment and Management

On a preventive basis ash trees can be protected from emerald ash borer infestations with a trunk injection of Tree-age for up 2 years with a 99% success rate. Tree-age can also be used as a treatment for post infestation as long as there isn’t more than 40% dieback within the canopy. However, the consequence of any significant amount of canopy decline can seriously affect the life expectancy of a tree.

If the diameter of a tree is more than 12”, we recommend a biannual Tree-age trunk injection at the proper dosage per diameter inch. However, if it is less than 12” in diameter, we recommend an annual insecticide soil injection of Xtect or Merit. Soil injections for EAB can be performed in spring or fall.