How to Get Rid of Banded Ash Borer Beetles in Denver

Spring is in full swing and you’re probably enjoying the warmer temperatures and the opportunity to get out and spruce up your landscape. Of course, you’ve been warned about the upcoming rise of Emerald Ash Borer in the Denver Metro area, but did you know that there’s another pest in town? The Banded Ash Borer Beetle is beginning to emerge now and will prey on your susceptible trees. Learn more about this threatening pest and how to act now to protect your trees and shrubs.


What Is the Banded Ash Borer Beetle?

Banded Ash Borer Beetles are native to the forests of North America, unlike the more notorious Emerald Ash Borer which originates from Asia. Visually, it’s pretty easy to distinguish one pest from another. While an adult Emerald Ash Borer boasts a showy metallic green exterior, the adult Banded Ash Borer is dark grey or black in color, covered in fine hairs, with distinct white or yellow looped markings on its abdomen. Their cylindrical, elongated bodies ranging from 8–18 mm. Known as roundheaded borers, Banded Ash Borer larvae are off-white with a dark, round head capsule. 


The next important thing to know about the Banded Ash Borer is how it affects trees over their life cycle. This wood-boring beetle does harm to stressed trees by tunneling under the bark, deep into the tree where it cuts off access to nutrients and weakens limbs. Here’s a snapshot of the Banded Ash Borer’s life cycle and damage timeline:

  • Adults survive the cold weather months by overwintering under tree bark
  • Adults emerge in spring, reproduce, and lay fresh eggs on the bark
  • Larvae begin by feeding under the bark in the phloem and later in the sapwood
  • Larvae pupate and develop in the fall
  • Larvae are the true damaging stage, primarily in late spring and early summer
  • Banded Ash Borers produce one generation per year


Understanding the banded ash borer’s lifecycle is important to proactive treatment and protecting your trees and shrubs. Luckily there is still time this spring to prevent Banded Ash Borer damage, but you need to act fast. The best thing you can do as a homeowner is to take advantage of our free property assessments. Our trained Fielding Tree & Shrub Care arborists can quickly sweep the area for signs of pests and evaluate the overall health and wellness of your trees, providing expert recommendations for next steps.


What Types of Trees Does the Banded Ash Borer Beetle Attack?


Not all trees are subjected to the devastating attacks by Banded Ash Borer Beetles. In Denver, we’re seeing Ash, Oaks, Elms, and Lindens as the species being primarily targeted. Stressed trees and newly planted trees are at especially high risk for attack because they do not have the healthy system needed to fend off pests. In addition to these types of trees, newly-cut, green logs with the bark still attached are very attractive to egg-laying Banded Ash Borer females.


What Kind of Damage Does the Banded Ash Borer Beetle Cause?

We’ve established which trees are at risk, but the real concern is what kind of damage can Ash Borer Beetles do? Here’s a brief overview from Virginia State University Extension:


  • Larval tunneling in standing trees may weaken limbs, making them more susceptible to breaking in high winds. 
  • Economic damage by Banded Ash Borer larvae is largely limited to hardwood intended for lumber or firewood. 
  • Adult Banded Ash Borer Beetles may be found in homes after emerging from firewood brought inside during the winter.


In a worst-case scenario, unhealthy trees can be outright killed by the Banded Ash Borer in a single season. More often than not though, these pests do structural damage that weakens and kills individual limbs making them an unsafe liability on your property.


Battling these beetles begins with knowing your trees. Not sure what types of trees you have on your property? No worries! Our arbor experts can talk you through it during a free property assessment. Knowledge is power. Let us help you take the first step to protect and care for your trees: learning about what species you have and their unique needs.


What Proactive Treatment Options Are Available?


It’s clear that tree damage caused by the Banded Ash Borer Beetle is completely preventable, but it is up to you to make it happen. Proactive pest management is a science, not a DIY project. This is not the time to try Wikipedia landscaping hacks for pest control! At Fielding Tree and Shrub Care, we have developed a tried and true field-tested four-step approach to treating trees. Here’s what you can expect from our professional team:


Step 1  We start with a complimentary on-site disease diagnosis of your trees and/or shrubs. If you’d like to expedite the process a bit, you can send us pictures in advance that may be able to help us reach our diagnosis more quickly.


Step 2  We then work to cure the disease or at least slow it down. We will discuss the viable treatment options available for your tree or shrub’s unique situation. We will also present the potential benefits and drawbacks of each treatment along with our professional recommendation for whichever solution we believe to be best.


Step 3  A proactive approach is implemented to protect your existing trees from disease or infestation. In the case of diseases and infestations, an ounce of prevention is truly worth the proverbial pound of cure.


Step 4  Unfortunately, sometimes trees and shrubs die, even with our best, safest, and most proven treatment solutions. If your tree or shrub dies, we try to remove the dead plant as soon as reasonably possible. This keeps your property safe from unnecessary infestations and unsightly rotting trees or shrubs.


Our four-step process yields consistently positive results. With attention to detail and seasoned expertise, our arborists can catch signs of infestation before they become full-blown problems. In addition, our team can make recommendations for custom tree care plans to help your trees stay in tip-top shape. This allows them to stay healthy and naturally fight off pests on their own.


Preventative Insecticide Treatments

Insecticides are available to effectively treat your trees that may be threatened by the Banded Ash Borer Beetle. Insecticides work best on trees that are still relatively healthy. However, if insecticide treatment begins after the first signs of infestation it can stop additional damage, but it will not reverse any damage that has already been done. 


Insecticides that can effectively control Banded Ash Borers fall into four categories

  • systemic insecticides that are applied as soil injections or drenches
  • systemic insecticides applied as trunk injections
  • systemic insecticides applied as lower trunk sprays
  • protective cover sprays that are applied to the trunk, main branches, and foliage. 


Here are two types of treatment and delivery that we recommend for the best success:


  • Soil root injection to prevent Banded Ash Borer infestation: this is a two-year protection program. Studies have shown uptake is higher and the treatment more effective when the soil root injection product is applied at the base of the trunk where the density of fine roots is highest.


  • Direct tree trunk injection to protect against Banded Ash Borer infestation: This is three-year protection. One advantage of trunk injections is that they can be used on sites where soil treatments may not be practical, effective, or appropriate, including trees growing on excessively wet, sandy, compacted, or restricted soil environments. They also yield rapid results!


When it comes to preventative treatment, you are in luck because spring is the ideal time of year to apply insecticide treatment for Banded Ash Borer protection. The timing of the insecticide coincides perfectly with the life cycle of the Banded Ash Borer Beetle. If you choose to act now, you can successfully control the adults before any new eggs or larvae are produced. Once summer really sets in it will be too late!


The Importance of Tree Fertilization

Strong, healthy trees and shrubs can naturally defend themselves against pest attacks. Therefore, one of the best defenses you can give your trees is annual tree fertilization. Tree fertilization helps feed your trees the essential nutrients they need for healthy growth. 


Did you know that Colorado’s soil structure is compacted and scarce of nutrients? There’s a strong chance that your trees and shrubs may be undernourished. Tree fertilization helps break up the hard clay allowing for more room for root growth. This is the most important factor for establishing trees and preventing stress. Stressed trees are commonly targeted by both Banded Ash Borers and Emerald Ash Borers.


Colorado’s high-altitude desert soil is notorious for missing key nutrients that trees need to be healthy. Fertilization does not safeguard a tree from disease but it definitely increases a tree’s immunity to many diseases. Tree fertilization along with proper watering is by far the best thing a homeowner can do for their tree after pruning has taken place!


Team Up With Expert Arborists Today


The Banded Ash Borer Beetle is the new pest in town, posing a threat to all Denver Ash, Oaks, Elms, and Lindens.  Don’t leave anything up to chance! These pests will arrive and spread late this spring, but you can still have time to put a plan in place to protect your trees.


Contact one of our certified arborists at Fielding Tree & Shrub Care today for a free property assessment. They can explain how the Banded Ash Borer Beetle might personally affect your property, and go over all your customizable treatment and preventative care options.


Act now to save your trees and schedule your free property assessment with Fielding Tree & Shrub Care today!