THE TREE DOCTOR (aka The Plant Doctor)

The Emerald Ash Borer - Ash Tree Decline


David L. Roberts
David L. Roberts, Ph.D.
Senior Academic Specialist
Michigan State University
Discoverer of the Emerald Ash Borer
The Emerald Ash Borer, a metallic green beetle
A new exotic beetle that has been killing ash trees in southeastern Michigan was identified last week as Agrilus planipennis.  The common name of the beetle as suggested by this discovery is the "Emerald Ash Borer (EAB)"
  (Fig. 1 Adult )  July, 2002
The Emerald Ash Borer, a metallic green beetle
Photo courtesy of Ken Chamberlain, OSU/OARDC 
EAB larvae on a lens cap
Several insect borer larvae, believed to be the two-lined chestnut borer, taken from a declining ash in the fall 2001. Larvae 26-32 mm in length, are cream colored, dorso-ventrally flattened, and have a pair of brown pincer like appendages on the last segment.  (Fig. 2a)



EAB Larvae Stages


Different sizes of EAB larvae
Mixed larval stages collected from single location on tree. 
Maybury State Park, MI  August, 2002 
EAB larvae within an Ash tree
Larvae feeding in Ash - Photos courtesy of David Cappaert
Larvae within a delining ash tree
An ash log kept over winter reveals four Larvae found when bark chipped away.  They become active under the bark with the onset of spring/summer warmth until emerging as an adult EAB insect. Photo D. Roberts - March, '03