Illinois Natural History Survey Reports

              1
ILLINOIS
NATURAL
HISTORY
SURVEY R e p o r t s
Autumn 2004
No. 381
I N S I D E
The Illinois Gap
Analysis Project
2
Frequency of Early
Mortality Syndrome in
Southwestern Lake
Michigan Lake Trout
Populations
3
Neartic Therevid
Genera Revision Nears
Completion
4
New INHS
Publications
5
Species Spotlight:
Spiny Softshell Turtle
6
Naturalist's Apprentice:
Turtle Crossword
Puzzle
7
Continued on back page
Hyalella azteca, a type
of amphipod crusta-cean
that is sensitive to
sulfate toxicity in
Illinois streams. Photo by
Michael Jeffords, INHS Office
of the Chief
Emerald ash borer adult and emergence hole. Photo by Phil Nixon, University of Illinois
Emerald ash borer, Agrilus
planipennis, is an insect new to
North America that attacks and
kills healthy ash trees. Its native
range includes
China, Korea,
Japan,
Mongolia, the
Russian Far
East, and Tai-wan.
It was first
identified in the
Detroit, Michi-gan
area in July
2002. Since
then it has also
been found in
other areas of
Michigan, the
Windsor,
Canada area,
areas of Ohio,
and other loca-tions
outside of
the Midwest.
Ash trees are important in our
residential landscapes, towns,
cities, and forests in Illinois. In
many communities, ash trees
comprise 10
to 20 percent
of the trees.
Adult
beetles are 1/3
to 1/2 of an
inch long and
elongate with
metallic em-erald
green
wing covers
on a green-ish-
bronze
body. They
emerge primarily in late spring
through 1/8-of-an-inch-wide, D-shaped
holes in the bark of ashes.
Adult beetles are present through
June into mid-July. After mating,
the female inserts her eggs, one
or two at a time, between bark
flakes.
The eggs hatch into larvae that
tunnel through the bark into the
cambium where the water, nutri-ent,
and sugar conducting tissues,
the xylem and phloem, are lo-cated.
The larvae are white, elon-gate,
and flattened, growing to
about 1 1/2 inches long. The lar-vae
pupate in the cambium and
emerge the following spring.
The larvae create slender,
winding tunnels that frequently
wind back and forth, creating a
series of S-shapes that run into
one another. Just as commonly,
the tunnels meander under the
bark with no particular pattern.
As the tunnels become numerous,
they effectively girdle a branch
causing it to die due to lack of
water and nutrients.
Emerald ash borer attacks the
top of the tree first, causing die-back.
Attack continues down the
tree, resulting in the gradual
death of branches until the entire
tree dies in two to three years.
The bark on attacked trees sepa-rates
from the tree trunk, allow-ing
the larval tunnels to be easily
seen. Once the tree dies to the
ground, suckers form around the
base of the trunk, but they do not
grow into strong, attractive trees.
The Morton Arboretum in
Lisle, IL, sponsors an Illinois
emerald ash borer readiness
group whose purpose is to pre-pare
the state for the possible
occurrence of this pest in Illinois.
Emerald Ash Borer, a Potential New Illinois Pest
Map courtesy of U.S. Forest Service