Quad-Cities Online, IL
05-19-07
Ashes to ashes? Exotic beetle targeting Illinois trees
By Brandy Welvaert, bwelvaert@qconline.com
Blackhawk Area
Special Education District
Supervisor
Great criminals leave unforgettable calling cards. The Riddler has his question
marks, and Zorro had his sword-shorn Zs.
The emerald ash borer, an exotic beetle that has gnawed its way across Ohio,
Michigan, Indiana and now parts of Illinois, announces its disastrous presence
with an indelible D.
Entomologists and horticulturists are keeping their fingers crossed that the insect
-- which is active now through August and leaves perfect D-shaped holes in ash
trees -- doesn't show up in the Quad-Cities.
"We're hoping not, but more and more, it's looking like `when' instead of `if,' "
says horticulturist Duane Gissel, with Iowa State University's Scott County
Extension.
The beetles first were found in the United States in 2002. They can fly about five
miles in their lifetimes, but people unwittingly have helped them move by
transporting firewood and landscaping materials that contained the beetles.
After Dutch elm disease wiped out millions of American elms in the middle of the
last century, ash trees often were planted in their place. They may have been
overplanted, Mr. Gissel says.
If the ash-borer infestation reaches the Quad-Cities -- it's already in Cook and
Kane counties in Illinois -- neighborhoods could lose about one in every five
trees, according to some estimates.
So what should you do if you have an ash tree? First, remember that the beetles
haven't been spotted here yet; and second, keep an eye out for them.
Mid-May is the time to check ash trees, says entomologist Phil Nixon with the
University of Illinois Extension. The extension has gone so far as to name May
20-26 Emerald Ash Borer Awareness Week.
Emerald ash borers are a bright, metallic green, and they have half-inch-long,
bullet-shaped bodies. They leave tiny, 1/8-inch exit holes in ash trees -- and ash
trees only -- in a D-shape.
"The D shape is distinctive. It's made by the shape of their body coming out of
the tunnels in the bark -- perfectly flat on the bottom and rounded on the top," Mr.
Nixon says. Some native beetles -- never the emerald ash borer -- create round
or oval-shaped holes in ash trees, according to the extension.
Other signs of infestation may include an unhealthy tree canopy or woodpecker
activity, says ISU entomologist Mark Shour in Ames.
Though ash trees may leaf out a bit later than usual this year because of the April
frost and snow, a healthy canopy of leaves will be a good sign, Mr. Shour says.
Since woodpeckers eat ash-borer larvae, their activity can be a symptom of
infestation. Suckers, or water sprouts, that grow from the major branches or the
trunk of a tree can be another signal of problems.
When it comes to using chemicals to prevent possible infestations, there isn't an
easy answer, Mr. Shour says.
The insecticide imidacloprid, sold in garden centers only as Bayer Advanced
Garden Tree and Shrub Insect Control, has been proven effective for preventing
emerald-ash-borer infestations, but not everyone agrees about its use.
"Some people believe that if they do a preventative treatment, regardless of
having a pest there, it will increase the tree's growth. The other side says if you
don't have a pest now," don't use a potentially harmful pesticide, he says.
It's also important to note that pesticides are not 100 percent effective, and that
they must be applied to trees each year.
In some areas where emerald ash borers already are a problem, governments
are removing all ash trees, regardless of whether they have been sprayed or
infested, in an effort to stop the beetles' spread.
Once ash borers infest a tree, it's probably too late to save it, Mr. Gissel says.
Still, if you happen to spot an emerald ash borer, call your county extension office
for help. (See story on DX for contact information.)
In the meantime, Iowa State University encourages homeowners to guard the
health of their ash trees by watering them, being careful not to crash into their
trunks with a lawnmower, and not parking vehicles atop their root systems, Mr.
Shour says.
In urban settings in Iowa alone, it's estimated that 15 million to 20 million ash
trees provide shade for homes in the summer and a buffer from the wind in
winter. If these valuable trees were wiped out, "we would see increased heating
and cooling costs, as well as increased watering costs" for lawns and new trees,
Mr. Shour says.
In the bi-state area, the actions of individuals can have a big impact on whether
the emerald ash borer makes it to Iowa at all.
To prevent the spread of the little green monster, the Illinois Department of
Agriculture has issued a quarantine of potentially infested materials. Illinois
residents are asked not to bring any dried wood, such as firewood for camping,
into Iowa.
The little green monster
Is that an emerald ash borer? Here's how to tell. Emerald ash borers:
-- Are a bright, metallic-green color.
-- Are about 1/2 inch long with bullet-shaped bodies.
-- Leave tiny, 1/8-inch-wide, D-shaped holes in ash trees, and ash trees only.
Extension contacts
If you find an emerald ash borer, call your county extension office.
University of Illinois Extension offices:
-- Rock Island: (309) 796-0512.
-- Henry-Stark: (309) 853-1533.
-- Henderson-Mercer-Warren: (309) 734-5161.
-- Whiteside: (815) 772-4075.
-- Knox: (309) 342-5108.
Iowa State University Extension offices:
-- Scott: (563) 359-7577.
-- Clinton: (563) 659-5125.
-- Muscatine: (563) 263-5701.