Emerald ash borer treatments near a vegetable garden
We have an ash tree that we are thinking about getting treated for emerald ash borer (EAB). It is not currently infected, but the EAB has been found a mile away from our house. The tree is directly uphill from our family vegetable garden (15 feet). Almost all runoff from one side of our yard runs right by the tree and into our garden. I am concerned about the pesticide (unsure of which one we would have applied) being leached into the ground and exposing our garden. What is known about the different treatments available and their effect on gardens? Is one treatment more "safe" than others?
Polk County Iowa
Thank you for your message and for contacting Iowa State University.
Here is a link to our emerald ash borer treatment pamphlet (downloadable file). https://store.extension.iastate.edu/Product/Emerald-Ash-Borer-Management-Options
Please note the timing for treatment is April to mid-May. Treating now will be less effective.
An injection treatment by a professional applicator puts all of the insecticide INSIDE the tree. There is none on the ground or in the soil to move to the garden. This will be your lowest risk treatment option, but also the most expensive.
Soil injection by a professional applicator also limits your risk by keeping the insecticide IN the soil where it is applied. There is little if any lateral movement through the soil.
The highest risk and lowest cost is treating the tree yourself (an option for small trees less than 20 inches in diameter). In the DIY treatment you drench the insecticide onto the base of the trunk of the tree. If that were to be followed by a heavy rain, the insecticide could move across the ground surface and what wasn't trapped by the turf could reach the garden. Chances are slim that would happen, and your awareness of the potential would lead you to make the application under carefully-chosen conditions.
Let me know if you have more questions. email@example.com
Thanks for your reply. This is very good information. What about the risk to tree professionals if the tree needs trimmed while the insecticide is active? The gentleman who does my tree work has told me that if I treat my tree, he will no longer work on it. He feels that the mist and dust released when cutting the tree is unsafe. And as you know, ash trees need a lot of annual maintenance, so this is a concern to me. Thanks again! Pete
I have visited with several specialists who work with EAB treatments and they are in agreement that the risk of exposure to insecticide while trimming or cutting injected trees is very, very low. What we have been told is that some insecticide remains in the phloem of the tree but that most is translocated to the leaves. The amount left in the phloem is low and the portion of the tree contacted by the saw blade is minute. This potential concern does not appear to have been sufficiently investigated but the consensus is that the risk is low.
On the other hand, anything a business person does to reduce risk is up to them, including wearing personal protective equipment such as respirator and face shield, or declining jobs that appear too risky.
I know that's not a very good answer but it reflects the discussions I've had the past two days.