Emerald ash borer - Ask Extension
My tree service recommended injecting our ash tree with insecticide. Is putting holes in the trunk of the tree safe long term? Our ash tree has a tr...
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Emerald ash borer #856538
Asked December 20, 2023, 11:36 AM EST
My tree service recommended injecting our ash tree with insecticide. Is putting holes in the trunk of the tree safe long term? Our ash tree has a trunk girth over 100” and is approximately 60 years old. The service indicated this injection will need to be done every 2 years. I am very concerned about putting holes in the trunk of the tree every 2 years.
Thank you in advance for your help.
Arapahoe County Colorado
Expert Response
Hi Laurie,
This is a great question. Drilling holes into a tree creates small tree wounds. The tree's response to the drilling will depend on health and vigor of the tree overall. Research has shown healthy tree will be able to produce new wood that covers in wounds in a matter of months. While generally trunk injections are very successful, there is still a risk involved with injuring the tree. If you are in an EAB-infested area, the risk is minimal compared to risk of losing your tree to emerald ash borer (EAB). EAB is is deadly to all ash trees.
Trunk injections to treat EAB are one of the most effective ways to save your tree from EAB. Since the insecticide is directly injected into the tree, there is no chance for run-off in the soil.
Regardless of which product/methods you choose, be sure to keep the soil moist for at least 4 weeks after the insecticide is applied. This will help the tree distribute the insecticide throughout the tree.
What part of Arapahoe County do you live in? EAB was found in the northeast portion of Littleton last June. EAB spreads slowly. Unless you are in the surrounding vicinity of northeast Littleton, you have some time to make a decision. If you choose to start treatments in 2024, spring time will be optimal time. Feel free to email me. I am happy to walk through the options for treatments. My email is <personal data hidden>.
If the arborist is treating your tree every two years, the active ingredient is emamectin benzoate. Extensive research has been done on ash trees with this product, and it is very effective. In fact, recent research has shown that you can start treatments with emamectin benzoate AFTER EAB has infested the tree if the tree hasn't lost more than about 30% of the canopy and is healthy.
Here is a fact sheet that outlines the four options: https://extension.colostate.edu/docs/pubs/insect/05626.pdf
For more in-depth information about treatments, click here: https://extension.missouri.edu/media/wysiwyg/Extensiondata/Pub/docs/v00001/EABinsecticide.pdf
More info on EAB in Arapahoe County: https://www.arapahoeco.gov/your_county/county_departments/open_spaces/our_work/emerald_ash_borer.php
Please let me know what other questions you have!
Thanks,
Lisa
Lisa Mason
Horticulture Specialist & Entomologist
Colorado State University Extension in Arapahoe County
This is a great question. Drilling holes into a tree creates small tree wounds. The tree's response to the drilling will depend on health and vigor of the tree overall. Research has shown healthy tree will be able to produce new wood that covers in wounds in a matter of months. While generally trunk injections are very successful, there is still a risk involved with injuring the tree. If you are in an EAB-infested area, the risk is minimal compared to risk of losing your tree to emerald ash borer (EAB). EAB is is deadly to all ash trees.
Trunk injections to treat EAB are one of the most effective ways to save your tree from EAB. Since the insecticide is directly injected into the tree, there is no chance for run-off in the soil.
Regardless of which product/methods you choose, be sure to keep the soil moist for at least 4 weeks after the insecticide is applied. This will help the tree distribute the insecticide throughout the tree.
What part of Arapahoe County do you live in? EAB was found in the northeast portion of Littleton last June. EAB spreads slowly. Unless you are in the surrounding vicinity of northeast Littleton, you have some time to make a decision. If you choose to start treatments in 2024, spring time will be optimal time. Feel free to email me. I am happy to walk through the options for treatments. My email is <personal data hidden>.
If the arborist is treating your tree every two years, the active ingredient is emamectin benzoate. Extensive research has been done on ash trees with this product, and it is very effective. In fact, recent research has shown that you can start treatments with emamectin benzoate AFTER EAB has infested the tree if the tree hasn't lost more than about 30% of the canopy and is healthy.
Here is a fact sheet that outlines the four options: https://extension.colostate.edu/docs/pubs/insect/05626.pdf
For more in-depth information about treatments, click here: https://extension.missouri.edu/media/wysiwyg/Extensiondata/Pub/docs/v00001/EABinsecticide.pdf
More info on EAB in Arapahoe County: https://www.arapahoeco.gov/your_county/county_departments/open_spaces/our_work/emerald_ash_borer.php
Please let me know what other questions you have!
Thanks,
Lisa
Lisa Mason
Horticulture Specialist & Entomologist
Colorado State University Extension in Arapahoe County
Lisa,
Thank you for your response. I truly appreciate it and we are planning on injection based on your information. Our tree is beyond healthy and we are very vested in keeping it that way. We would truly miss all the benefits it creates if we lost it.
We live near Arapahoe and Broadway in Littleton and are planning to inject our tree in the spring. We use Sava Tree as our service, I will plan to double check the insecticide they use and make sure it is what you recommend. We also have a Linden we inject the soil for Japanese Beetles in May every year. So far this has been a wonderful deterrent for the beetles without impacting the bees that love it so.
Thank you again for the links and information.
Laurie Stragand
