Does Your Ash Tree Have the
Emerald Ash Borer?
If you live in Illinois, at this time the answer to the title question
is most likely “No.” There have been numerous stories
in the local newspapers regarding the emerald ash borer and the
devastation it has caused to ash trees in Michigan, Ohio and Indiana.
This is making homeowners examine their trees. Many are finding
holes in their trees and worrying that the tree has this new insect.
What most people don’t realize is that there has been another
type of ash borer in our area for many, many years. It is commonly
attracted to ash trees that are under stress and while it can kill
the tree, this is often a slow process and good maintenance of the
trees coupled with insecticide treatment at the proper time can
minimize the damage.
The emerald ash borer often does a lot of damage quickly. According
to the USDA Forest Service, many trees lose as much as 30-50 percent
of their canopy in one year and the tree is often completely killed
in 2-3 years.
So, how do you know which borer is in your tree? Look at the holes
made. The ash borer we commonly see here makes a round hole, about
1/8-1/4 inch in diameter. The hole of the emerald ash borer is shaped
like a ‘D’ with one side being distinctly flat.
At this time, we should not panic about the emerald ash borer,
but we should be on the look out for it. The excerpt quoted below
is from Dr. Phil Nixon, University of Illinois Entomologist.
"Movement of this pest from infested areas is most likely
on firewood and nursery stock. This pest was detected and identified
in North America in July 2002, but estimates are that it has been
in southeastern Michigan for 8 to 10 years. Ashes moved out as nursery
stock during that time could easily have been infested. This beetle
is common in younger as well as older trees. If you obtained nursery
stock from that area during the last 10 years, scout areas where
it was planted for signs of this beetle.
Infestations have been found in Michigan in green, white, and
black ash. It would likely attack blue ash as well, but that plant
is not common in southeastern Michigan. In Asia, it attacks Ulmus
davidiana var. Japonica, used in some crosses for American
elm replacement varieties. Look for 1/8-inch, D-shaped holes in
the bark—similar to exit holes of bronze birch borer. Infested
ash trees first show dieback of upper branches, progressing to death
of major branches, water sprouts on the trunk, and finally, water
sprouts at the base of the otherwise dead tree. If suspects are
found, contact the Illinois Department of Agriculture.”
October/November 2004: Diseases
and Insects of Shrubs and Small Trees | Does Your Ash Tree Have
the Emerald Ash Borer? | Harvesting and Storing
Pumpkins, Winter Squash, and Gourds