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The Emerald Ash Borer Continues West

It’s official, the Emerald Ash Borer has been recorded in South Dakota. More than 250 infested trees have been found in the state’s largest community of Sioux Falls. For those of you who haven’t heard of this destructive little beetle, here’s a brief introduction to the epidemic we’re facing. The Emerald Ash Borer(EAB) is an Asian beetle that was introduced in Michigan in the 1990’s, likely hitching a ride in a wooden shipping crate through the Great Lakes. After it’s introduction into an area outside of it’s native range, the EAB is able to spread like wildfire because unlike a native insect like the Pine beetle, the ecosystem has no natural control systems in place to deal with the infestation. The EAB spares no Ash trees that go untreated. Throughout it’s spread across 33 states in 16 years, it has killed more than 60 million Ash trees despite rigorous local efforts to slow it down. The most common way for the EAB to spread is through people moving infested materials such as firewood, logs, branches, nursery stock, chips or other ash wood. It also spreads naturally through beetle flight, and is very good at locating any Ash trees within 15 miles of where it emerges. According to the South Dakota Dept. of Ag, our statewide urban forest consists of at least 33% Ash, meaning the EAB will never have to fly far to find it’s next victim. It is estimated that there are more than 1.58 million Ash trees in South Dakota with a replacement cost of over $10 billion. This is an epidemic that has been many years coming and it is inevitable that it will continue to spread across South Dakota and the rest of the Western United States.

What does this mean for us here in the Black Hills? It doesn’t seem to be an emergency quite yet, and we don’t need to rush out and start treating our trees because it could potentially be years before it finds it’s way here. That being said, there’s no reason that it can’t already be here. Given that we are right on the I-90 corridor for vacationers travelling between cities that have reported incidences, it is quite likely that infested wood has already passed through. At this point we all need to be vigilant in keeping an eye out for signs of our community being under attack of the pervasive EAB. Here’s what to look out for, and should you think you see any of these signs, call a local arborist immediately to come out for a closer look.

Checklist to determine if your tree may be infested by Emerald Ash Borer

If you believe you found a tree infested with EAB, do the following check:

- Is it an ash tree?

- Is bark peeling off from woodpecker activity?

- Are there vertical splits in the trunk?

- Are there serpentine galleries just beneath the bark that are filled with a powdery substance?

- Are there crisp 1/8-inch D-shaped exit holes on the trunk or branches?

The South Dakota Department of Agriculture has a great website for following through with this checklist along with in depth pictures and all the information you need on EAB.


Knowledge and community action will be key in fighting this thing together.

Alan Enderson

ISA Certified Arborist # MW-5809A

#emeraldashborer #EAB #southdakota #urbanforestry #arboriculture #ashtree

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