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Little killers: Emerald ash borers have arrived

Experts urge proactive approach to protect trees

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MORRISON – The first emerald ash borer beetle was found in Whiteside County last week, marking the western-most confirmed sighting in Illinois.

The beetle, which is metallic green and about a half-inch long in adulthood, poses a serious threat to ash trees. According to Scott Schirmer, emerald ash borer program manager with the Illinois Department of Agriculture, if the beetle goes unchecked, it could lead to the extinction of ash trees, though he doesn’t foresee that now.

“It’s way beyond Dutch elm [disease] right now,” Schirmer said. “Emerald ash borer is considered the most destructive, invasive forest pest North America has ever seen.”

After an adult beetle was found at the county fairgrounds in Morrison, Jeff Squibb, a spokesman for the IDOA, said Whiteside County would be added to the state’s quarantine list, which already includes Lee and Ogle counties. The list will be updated in the fall.

The beetle was found in Lee County in September 2012.

The quarantine list prohibits residents from moving ash trees, or their limbs or untreated products, outside of a quarantined county. Experts say the beetle moves faster when aided by humans than it would on its own.

The beetle can move about 1 to 2 miles a year without assistance, Schirmer said, and will naturally travel to where it finds an abundance of ash trees. But with the assistance of humans, the beetle has traveled much faster.

He said the beetle that was found in Morrison could have been moved there by a car, on a nursery tree planted 15 years ago, or even on firewood. If the beetle had been there for 6 years, it would have been moved before many of the quarantine lists were established in the state.

“I think one of the most significant misconceptions or misunderstanding is that you can be successful when you’re reactionary to it,” Schirmer said. “Our estimates are that it had been in the tree for 6 years. It can go undetected and go into stealth mode for years.” 

Schirmer said preparation, awareness and being proactive are the best defenses. He urged people who have an ash tree on their property to treat the tree while it’s healthy, not once it shows symptoms.

Ash trees are defined by their opposite branching and budding structure, which form a V, Schirmer said. Ash are among the few trees that have opposite branching and budding structure, he added.

“Most people have a tendency to be more reactionary,” Schirmer said. “This bug keeps showing us a reason to believe that we can’t do that.”

The beetle, which is native to Asia, first was detected in the U.S. in 2002, in Detroit, and has killed more than 25 million trees since then, the IDOA said in a statement.

Symptoms include thinning and yellowing of leaves, and D-shaped holes in the bark, branches, trunk and basal shoots, the IDOA said.

The decision whether to treat an ash tree or to remove and replace it can involve several factors. Homeowners who place a high sentimental value on a tree or have a tree that adds to the property value may choose treatment, Schirmer said.

Schirmer recommends residents go to www.TreeBenefits.com while making the decision between treatment and removal. The website calculates the monetary value a tree can have for a homeowner.

Over-the-counter treatments have shown success, Schirmer said. But if a resident is in an area where another tree has been affected, or if a resident is worried, he should contact an expert.

Defending against the beetle

The larva hatches and burrows into the cambium, which is like human stem cells, Schirmer said. It then feeds on the vascular tissue and strangles the tree.

Infected trees can’t transport water and nutrients the same as healthy trees, and they slowly die. Schirmer compared it to putting a tourniquet tightly on your arm to cut off blood flow.

The D-shaped holes in the bark are created when an adult beetle leaves the tree, said Alan Skoog, owner of Skoog Landscaping and Design, 2612 W. LeFevre Road, in Sterling. As a result, once a resident sees those marks, the tree already has been attacked.

Skoog’s company uses an insecticide called TREE-age, which is made by Arborjet Inc., and is injected directly into the ash tree.

Depending on the size of the tree, a technician drills about four five-eighths-inch holes into the base of the tree and inserts a plug. Then, every 2 years, the insecticide is injected into the tree. While no treatment is guaranteed to be 100 percent effective, Schirmer and Skoog said, treatments can extend the life of a tree and be financially, as well as sentimentally, beneficial for homeowners.

The cost of treatment can vary, Skoog said, depending on the size, location and number of trees. The cost of removing a tree also varies depending on similar factors, he added.

But treating a tree early, before others in the general area have been impacted by the beetle, will help to stop the spread, experts said. A tree has a better chance to survive if the insecticide gets into the tree before the larva.

Skoog said ash trees shouldn’t be treated after Sept. 1, when the tree’s sap doesn’t flow as much through the vascular system.

“The long-term impact is, any ash tree that’s not taken care of, is not treated, is going to be dead,” Skoog said. “And I’ve seen it stated as quickly as 5 years.”

Municipalities prepare

Area municipalities are taking different approaches to prepare for a possible invasion of emerald ash borer beetles. Some have chosen to remove all ash trees, while other will go with a mixture of treatment and removal.

Carol Chandler, of the Dixon Tree Commission, said Dixon has about 374 ash trees, and 147 of them on the city’s rights-of-way.

“It’s rather a pervasive thing,” Chandler said. “It’s like the Dutch elm disease. We’re going to do what we can. [We] don’t have high hopes, though. We can only do what we can.” 

She said the city already had treated about 50 ash trees, but will not treat trees deemed too old or too young, as experts say those trees won’t absorb the treatment well. Those trees not treated, Chandler said, will be removed and replaced with a variety of species.

Replacing removed ash trees with a variety, experts said, is an important step to ensure the next threat to a specific tree won’t have as big of an impact.

Sterling has decided to remove all ash trees, about 200 of them, according to Hadley Skeffington-Vos, assistant to the city manager. She said the decision was a result of spotty reviews of some treatments and not being able to treat young or old trees. 

Beginning in the 2013-14 fiscal year, the city will start a 10-year process to remove its ash trees, about 20 a year, and replace them with a variety of species. The city will plant two trees for every ash tree it removes.

Sterling will spend about $240,000, divided evenly each year, for tree removal.

Rock Falls started its emerald ash borer plan this past fall, said Ed Cox, the city’s wastewater superintendent, who also is overseeing the program. 

The city has treated 24 trees on its property, and the remaining seven ash trees will be removed. The city has no plan to replace the removed trees, Cox said, because many were stand-alone or in odd locations.

Morrision, the location of the lone confirmed report of the emerald ash borer beetle in Whiteside County, has recently begun an inventory of its ash trees. Director of Public Services Gary Tresenriter said it was too early to determine whether the town would treat or replace those trees.

What does a quarantine mean?

Whiteside County will join 41 counties – including Lee and Ogle – that already are quarantined because of the emerald ash borer.

The quarantine prohibits the removal of the following items from a county:

• The emerald ash borer in any living stage of development

• Ash trees of any size

• Ash limbs and branches

• Any cut, nonconiferous firewood

• Bark and ash wood chips larger than 1 inch

• Ash logs and lumber with either the bark or the outer 1-inch of sapwood, or both, attached

• Any item made from or containing the wood of the ash tree that is capable of spreading the emerald ash borer.

• Any other article, product or means of conveyance determined by the Illinois Department of Agriculture to present a risk of spreading the beetle infestation.

Go to www.IllinoisEAB.com or call 217-785-5575 for more information.

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