Ash borer report unfounded, but authorities remain on alert
Springfield State Journal-Register
A reported infestation of emerald ash borer in Christian County has proved to be a false alarm.
“Our staff examined the tree in Christian County and determined that, while it had been infested by beetles, they weren’t emerald ash borer beetles,” said Jeff Squibb, spokesman for the Illinois Department of Agriculture. The diseased ash tree had been reported by a crew from Ameren working in Pana May 11.
The emerald ash borer was confirmed on the east side of Decatur recently, but the beetle has not yet been found in Sangamon County.
Central Illinois residents are on the lookout for the destructive pest, so experts want people to know the signs of emerald ash borer infestation.
“The general accepted practice is there are four signs or symptoms we associate with emerald ash borer,” said Scott Schirmer, emerald ash borer program manager with the Department of Agriculture.
* Canopy dieback within the crown of the tree. “You will see holes in the canopy and branches with leaves not coming out,” Schirmer said.
* Epicormic growth, also known as water sprouts or suckering, may be evident. “When the emerald ash borer attacks a tree, the branches literally will be strangled,” he said. “And as the tree dies and it struggles, young new branches pop out at the bottom. It is kind of a last-ditch effort to photosynthesize.”
* Bark splitting reveals galleries where larvae have tunneled. “As larvae eat below the cambium, the effect eventually will be similar to potholes in the road,” Schirmer said. “Bark will split open exposing galleries underneath.”
* Homeowners may notice increased woodpecker activity. “Woodpeckers really like to key in and eat those larvae,” he said.
Old trees, those outgrowing the spots where they were planted, or those planted in the wrong place may exhibit some of these same signs.
Tough to detect
Usually by the time emerald ash borer is detected, the insect has been in the area a few years.
“It’s very difficult even for us, the experts, to detect it very early,” Schirmer said. “Usually by the time we discover a tree that is infected or someone calls it in, they have usually been there two or three years.”
As generations reproduce, the number of borers present rises dramatically.
“It’s that third or fourth year of generations when you get into the hundreds or even thousands of larvae infesting the tree,” he said.
At the Illinois State Museum Research and Collections Center, Tim Cashatt, curator of zoology, pulls out drawers of insects with specimens sometimes mistaken for emerald ash borer.
The bug that gets most people excited is the six-spotted tiger beetle.
“It is metallic green and people often see it along trails,” Cashatt said of the sun-loving beetle.
But when Cashatt produces a vial with a tiny emerald ash borer not much longer than a fingernail, it is clear the tiger beetle looks nothing like it.
“It’s hard to believe this itty-bitty bug can cause so much destruction,” he says.
Schirmer said numerous native borers also go after ash trees, causing similar damage.
“The ash privet borer, ash lilac borer, red-headed ash borer — all are relatively common and native to the United States, so they don’t kill the tree,” Schirmer said. “Typically they are considered secondary infectors. They usually don’t come in until the tree is in decline.”
And those borers leave round or oval exit holes, not the diagnostic “D” shaped exit hole of the emerald ash borer.
“It almost looks like a half moon,” Schirmer said. “It is very flat on one side, very curved on the other side.”
Reports from the public that an emerald ash borer has been spotted don’t do much good if authorities can’t find the tree in question.
“If they can capture it, put it in a bag and freeze it, that is very helpful,” he said of the insect. “Try to collect the sample so we have something to go off.”
There are pesticides that work against emerald ash borer, but they must be applied every year or every other year, Schirmer said.
Those treatments are most effective if used in a preventive, not curative manner.
The chemical is carried through the tree by the same means as water and nutrients.
“If the vascular system is too disrupted or destroyed by emerald ash borer, the chemical won’t be distributed,” he said.
One common treatment is available over the counter. Licensed professionals must apply some other treatments.
“Bayer Advanced Tree and Shrub is the same product used for Japanese beetles in lawns and in flea collars,” Schirmer said.
“You can get it at farm supply stores or at the garden center and apply it yourself,” he said. “Mix with water and drench trunk of the tree.”
Guidelines recommend that treatment not begin until emerald ash borer is confirmed within 15 miles.
Chris Young can be reached at 788-1528.
On the Web
Illinois Department of Agriculture emerald ash borer page