Japanese maple Aphid infestation - Ask Extension
I have a 15 foot tall Japanese maple that is infested with aphids and ladybugs. I'm not concerned with the ladybug but the aphids are a concern for tr...
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Japanese maple Aphid infestation #897146
Asked April 12, 2025, 8:59 PM EDT
I have a 15 foot tall Japanese maple that is infested with aphids and ladybugs. I'm not concerned with the ladybug but the aphids are a concern for tree health. Also, tree SAP and and dead aphids are making a mess on my cars. Is there something I can spray that reaches the top of the tree to control the aphids but not hurt the ladybug
Polk County Oregon
Expert Response
Hello,
Low-toxicity pesticides can also harm beneficial insects (like ladybug larvae) if they are present when the insecticide is sprayed. However, such products typically do not have a long residual time, which means that the pesticides break down quickly and won't affect insects that arrive later on. Unfortunately, that also means that pest insects will not be affected long-term after the product is applied, and those that are not contacted by the spray will live.
You have a difficult situation since the tree is tall and spraying the top would be very challenging. That is always a risky situation, even with a low-toxicity product. Often aphids are an issue in early spring and will be less problematic as the weather warms up and as your lady bugs and other beneficial insects catch up to the aphid populations. You may be better off waiting for the aphid populations to subside on their own. If you do use an insecticide, read the label completely, and read the required Personal Protective Equipment required, especially if you are applying to an area that is difficult to reach.
Here is more information about low-toxicity insecticides, some of which are effective for aphids:
https://homegarden.cahnr.uconn.edu/factsheets/insecticides-low-toxicity-options/
Thank you for using Ask Extension!
Low-toxicity pesticides can also harm beneficial insects (like ladybug larvae) if they are present when the insecticide is sprayed. However, such products typically do not have a long residual time, which means that the pesticides break down quickly and won't affect insects that arrive later on. Unfortunately, that also means that pest insects will not be affected long-term after the product is applied, and those that are not contacted by the spray will live.
You have a difficult situation since the tree is tall and spraying the top would be very challenging. That is always a risky situation, even with a low-toxicity product. Often aphids are an issue in early spring and will be less problematic as the weather warms up and as your lady bugs and other beneficial insects catch up to the aphid populations. You may be better off waiting for the aphid populations to subside on their own. If you do use an insecticide, read the label completely, and read the required Personal Protective Equipment required, especially if you are applying to an area that is difficult to reach.
Here is more information about low-toxicity insecticides, some of which are effective for aphids:
https://homegarden.cahnr.uconn.edu/factsheets/insecticides-low-toxicity-options/
Thank you for using Ask Extension!
