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Emerald Ash Borer in Colorado!

Posted by idelle Z5 Denver (My Page) on
Fri, Oct 11, 13 at 0:31

Just in from my favorite tree company, Mountain High Tree -- the Emerald Ash Borer is here in the Front Range. These bugs are crazy - they've wiped out millions of Ash trees in the east, and now it sounds like they've arrived in Boulder! Sadly, once they get into your tree, it's doomed! Just like the other menace we're battling, the IPS beetle!

The only thing we can do to protect our Ash trees is to treat them with injections - Mountain High can help determine how best to protect our Ash trees. I'm going to have them come out to see what we can do to protect our young Autumn Ash tree. Learn more about the pest in their blog here:

Here is a link that might be useful: Emerald Ash Borer in Colorado

Follow-Up Postings:

RE: Emerald Ash Borer in Colorado!

I've got over a hundred, 16 year old green ash trees as a wind/visual break.

/not happy to hear this.

RE: Emerald Ash Borer in Colorado!

  • Posted by gjcore 5 South Aurora Co. (My Page) on
    Fri, Oct 11, 13 at 10:51

If they already have been detected in Boulder then they are probably in numerous other places along the front range so the time to act would be now.

From what I read a couple months back ash trees will need yearly treatments at a couple hundred dollars per tree.

RE: Emerald Ash Borer in Colorado!

I spoke with Ralph at Mountain High Tree about it, and he said that the injections can last up to several years in large trees, so it might not have to be an every year thing. But it is a real bummer that we have to start treating them or risk losing them! :( We should hire a flock of woodpeckers to eat them all! ha!

RE: Emerald Ash Borer in Colorado!

I've watched the progression for seveal years, when I heard it was in Kansas last year I knew it wouldn't be long.

Sure enough, I have the telltale borer holes and sawdust at the base of a Patmore I planted 5 years ago. It's not practical to treat ours, so I've been underplanting ours with oak, yellowwood, ginko, dogwood, etc. in preparation for when the ash go. It's frustrating for sure, but I'm trying view it as an opportunity to create some diversity in the yard.

Drought, fires and flood. We've really seen it all this last year!


RE: Emerald Ash Borer in Colorado!

I have a windbreak/visual break on two sides of my 3.5 acre property, a line of Scots pine on the exterior, and green ash on the interior. The Scots pine have been infected with pine bark beetles for years now, and I've only lost 4 or 5 - But boy, do the trunks look like they've been through the wars. Gnarly, sap blobs all over the place, wood pecker heaven. They even have the blue stain virus - so by all accounts they should be dead. But I guess since the trees can't read....

For several summers, I did spray the trunks with stuff containing Orthene, a systemic. But I have no idea if it helped or the trees just fought them off on their own. I was able to spray all the trees, twice a summer, for <$50.

Something to think about, anyway.

RE: Emerald Ash Borer in Colorado!

There are tree companies out there who use scare tactics to sell their EAB treatments. For unbiased information about EAB and treatments, you might take a look at the CO Dept. of Agriculture website.

Here is a link that might be useful: Emerald Ash Borer

RE: Emerald Ash Borer in Colorado!

  • Posted by Lesuko 5, Boulder CO (My Page) on
    Tue, Mar 11, 14 at 13:15

Hi Everyone-

Please see the City of Boulder's response to EAB. The injections that are most commonly used by tree companies are a neonicotinoid- a systemic pesticide that kills all organisms that come in contact with it. It is what has been wiping out bees all over the world. please DO NOT treat with this chemical. The Ash tree is a source of nectar and pollen for many beneficial insects and birds. They all die when they come in contact with it.

Please review the CO extension resources on EAB. They are recommending NOT to treat because the treatments are very harnful. They are also absorbed by surrounding plants and leached into our groundwater. Boulder will start a tree replacement campaign- that's how severe these chemicals are.

Please wait until more information becomes available before treating your trees.

Thank you for your email. Emerald ash borer (EAB) management on a municipal scale is quite complex and difficult given the need to balance the potential impacts of pesticide use with the reduction in environmental, economic and social services caused by the loss of a significant portion of our urban tree canopy. During the last few months, city staff has been gathering information about the number and quality of ash trees on city properties, and sampling ash trees throughout the city to estimate the density of EAB and map known areas where it has been detected. The city is developing a plan to slow the spread of EAB and this will include a number of management approaches, including tree removal and replacement and very limited and targeted pesticide application.
> > City Forestry and integrated pest management (IPM) staff are carefully evaluating all available products labeled for use against EAB for both effectiveness and potential non-target impacts. A research advisory group has been formed, that includes several of the leading EAB researchers from the Midwest and Canada. After careful consideration, the city has decided not to use the neonicotinoid, imidacloprid, for EAB on public property in 2014 or in the future and will not recommend its use to residents. If a decision is made to treat an ash tree, there are other products available that are significantly more effective and pose fewer potential impacts to non-target organisms.
> > The 2014 EAB work plan is currently being finalized and more detailed information will be available within the next few weeks.
> > If you have further questions or concerns, please feel free to contact either myself or Rella Abernathy, city IPM coordinator (, directly.
> > Thank you,
> Kathleen
> > Kathleen Alexander
> City Forester
> Parks and Recreation Department
> City of Boulder
> Phone: 303-441-3406

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