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Emerald Ash Borer

certified eab cure arborist


As a certified arborist and forester, it’s my job to keep trees healthy and vibrant. The emerald ash borer (also known as EAB) is the latest serious threat to tree life in the state of Colorado. Here’s a lowdown on some clear emerald ash borer information.

What is the emerald ash borer?

The emerald ash borer is an invasive species of insect native to Asia. This green (hence “emerald”) wood-boring beetle was discovered in Michigan in 2002 and found for the first time in Colorado in September 2013 in Boulder County.

Why should we be concerned about the emerald ash borer?

This insect attacks and kills ash trees, which make up about 15 percent of Colorado’s trees—most of these in neighborhoods, yards, and urban landscapes, because the ash is not a tree originally native to Colorado. It’s reasonable to expect that all of northeastern Colorado—and its suburban neighborhoods—will be infected with the emerald ash borer within 10 years.

Is that really all that dangerous?

Unfortunately, yes. American ash trees have no defenses against this non-native insect and left untreated, infections are almost always fatal. The Colorado Department of Agriculture tells us that since 2002 (when it was likely transported from Asia via wood packing materials), the emerald ash borer has been responsible for the death and decline of at least 50 million ash trees in 21 states.

How does the emerald ash borer compare with the mountain pine beetle?

The emerald ash borer is more than twice as destructive as the mountain pine beetle—an 8 on the danger scale, while the pine beetle is a 3.

What does EAB treatment consist of?

The best way to treat for emerald ash borer damage (or potential damage)—and the method I use—is with trunk injections. If you think of the tree as a living thing with a vascular system, the injection holes I drill function the same as an IV system in a human being.

What do you inject with?

The treatment I use is called TREE-äge. I use it because it’s the only pesticide that is labeled for curative properties, meaning it actually kills the bugs.

How often do infected trees need to be treated?

Once the treatment is in the tree, you have emerald ash borer protection for three years.

What are the signs my ash tree is infected?

Tiny D-shaped exit holes are the most telltale signs of infection. You also may see vertical splits in the bark or new sprouts on the lower part of the tree, and the leaves and branches may be sparse because the borers eat the tree leaves. Infected trees will also attract more woodpeckers.

How much does treatment cost?

Cost is one of the first questions I get from customers wanting me to treat their trees for emerald ash borer damage or potential damage. The short answer is it depends on tree size.

Think of it this way: Larger humans require increased dosages of medicine; similarly, the larger the tree, the more treatment it needs. Tree size is determined by what’s known as “diameter at breast height” (dbh), which is the measurement across the tree (not around it—that’s the circumference). Costs range from under $50 for 6-inch dbh to over $300 for 36-inch dbh. Drilling into a tree to determine the diameter isn’t practical, so I use a special measuring tape that automatically calculates the diameter when I “hug” around the tree. They don’t call us “treehuggers” for nothing!

How can I get my trees treated right now?

Have a certified arborist—like me —come to take a look at your tree. I’ll provide an estimate at no cost, or an in-depth consult complete with treatment plan at an hourly rate. (Travel fees apply for distances greater than an hour.)

Do I really have to treat my trees?

No, you don’t. Trees vary in importance to the individual. But keep in mind that untreated trees will die, and a couple hundred dollars for treatment can sound a heck of a lot better than a $2000 dead-tree removal fee.

Where can I find more information?

There is extensive and valuable emerald ash borer information on the Department of Agriculture’s EAB page. In addition, I’m happy to answer any questions you may have related to the emerald ash borer and advise you on your best course of action.



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