EAB trunk injections - Ask Extension
How long do the trunk injections protect the ash trees as long as the injections are done correctly. Does this protection window depend on the treat...
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EAB trunk injections #862436
Asked March 25, 2024, 10:33 AM EDT
How long do the trunk injections protect the ash trees as long as the injections are done correctly. Does this protection window depend on the treatment level ? Does this also depend on the type of pesticide being used (tree-age g-4) (tree-age R-10) etc. I have looked at the labels and have not found this info on the labels. Thank you for your time and response!
Arapahoe County Colorado
Expert Response
Hi Paul,
The trunk injections will last at least 2 years if you are using Emamectin Benzoate as the active ingredient.
Of the four insecticide options, both imidacloprid and diontefuran only last one year. Azadirachtin can last 2 years unless it's a peak outbreak.
Both Tree-age G4 and Tree-age R10 are emamectin benzoate products meaning both products will last 2 years. Tree-age R10 has a higher concentration of emamectin benzoate meaning it takes less time to inject the product into the tree. Both G4 and R10 will deliver the exact same amount of emamectin benzoate but since R10 has a high concentration, the dose requires less of the product saving time during the application. This can be a way to save time/money especially if the homeowner has many trees that need treatment. If applied correctly, both products are equally effective in protecting your ash trees.
For treatment level, do you mean application rate? The application rate, and number of injection holes depends on the tree's diameter. The arborist/pesticide applicator will also assess the health of the tree and level of infestation. They can choose to do a low, medium, or high dose. Those doses are standardized and included on the product label. For instance, see page two for the rate table for Tree-age R10. Here is the label for Tree-age G4. Regardless of the application rate, the product will work for at least 2 years.
Research has shown that emamectin benzoate can actually last up to 3 years. It is labeled for 2 years since that's very effective if applied correctly. To learn more about the research about lasting 3 years, I recommend reading page 14-15 of this PDF (or page 13-14 if you go based on the page numbers in the bottom corners of the pages).
The decision to treat every 2 or 3 years is a personal decision based on financial considerations, and the homeowner's peace of mind. Some homeowners prefer the guaranteed treatment every 2 years. Some would rather save money and resources, and treat every 3 years.
The game-changer with emamectin benzoate is that you can treat your ash trees AFTER emerald ash borer (EAB) has infested your tree, as long as your trees are healthy and haven't lost more than about 30% of the canopy. This allows homeowners time to make the decision on when to start treatment.
Be sure to keep your tree well-watered for a few weeks after the injections! Since EAB treatments are systemic, the roots need to be able to uptake the product and distribute it throughout the tree. A well-watered tree will be able to do this more efficiently.
Emamectin benzoate is most effective when it's applied mid-to-late spring just after the tree has leafed out.
I don't know what part of Arapahoe County you are living in, but we found EAB in a small area in northeast Littleton in June 2023. If you live in that area, it's advisable to start treatment sooner than later. As of today, March 25, 2024, we haven't found yet anywhere else in Arapahoe County or surrounding areas including the City/County of Denver, Douglas, etc. Since EAB spreads slowly, homeowners have time to decide when to start treatment. They have the option of waiting until EAB is closer to their neighborhood.
More info on EAB insecticides here.
Please let me know if you have any questions!
Thanks,
Lisa
Lisa Mason
Horticulture Specialist, Entomologist
Colorado State University Extension in Arapahoe County
<personal data hidden>
The trunk injections will last at least 2 years if you are using Emamectin Benzoate as the active ingredient.
Of the four insecticide options, both imidacloprid and diontefuran only last one year. Azadirachtin can last 2 years unless it's a peak outbreak.
Both Tree-age G4 and Tree-age R10 are emamectin benzoate products meaning both products will last 2 years. Tree-age R10 has a higher concentration of emamectin benzoate meaning it takes less time to inject the product into the tree. Both G4 and R10 will deliver the exact same amount of emamectin benzoate but since R10 has a high concentration, the dose requires less of the product saving time during the application. This can be a way to save time/money especially if the homeowner has many trees that need treatment. If applied correctly, both products are equally effective in protecting your ash trees.
For treatment level, do you mean application rate? The application rate, and number of injection holes depends on the tree's diameter. The arborist/pesticide applicator will also assess the health of the tree and level of infestation. They can choose to do a low, medium, or high dose. Those doses are standardized and included on the product label. For instance, see page two for the rate table for Tree-age R10. Here is the label for Tree-age G4. Regardless of the application rate, the product will work for at least 2 years.
Research has shown that emamectin benzoate can actually last up to 3 years. It is labeled for 2 years since that's very effective if applied correctly. To learn more about the research about lasting 3 years, I recommend reading page 14-15 of this PDF (or page 13-14 if you go based on the page numbers in the bottom corners of the pages).
The decision to treat every 2 or 3 years is a personal decision based on financial considerations, and the homeowner's peace of mind. Some homeowners prefer the guaranteed treatment every 2 years. Some would rather save money and resources, and treat every 3 years.
The game-changer with emamectin benzoate is that you can treat your ash trees AFTER emerald ash borer (EAB) has infested your tree, as long as your trees are healthy and haven't lost more than about 30% of the canopy. This allows homeowners time to make the decision on when to start treatment.
Be sure to keep your tree well-watered for a few weeks after the injections! Since EAB treatments are systemic, the roots need to be able to uptake the product and distribute it throughout the tree. A well-watered tree will be able to do this more efficiently.
Emamectin benzoate is most effective when it's applied mid-to-late spring just after the tree has leafed out.
I don't know what part of Arapahoe County you are living in, but we found EAB in a small area in northeast Littleton in June 2023. If you live in that area, it's advisable to start treatment sooner than later. As of today, March 25, 2024, we haven't found yet anywhere else in Arapahoe County or surrounding areas including the City/County of Denver, Douglas, etc. Since EAB spreads slowly, homeowners have time to decide when to start treatment. They have the option of waiting until EAB is closer to their neighborhood.
More info on EAB insecticides here.
Please let me know if you have any questions!
Thanks,
Lisa
Lisa Mason
Horticulture Specialist, Entomologist
Colorado State University Extension in Arapahoe County
<personal data hidden>
