Pest identification Request - Ask Extension
Hello, we have two Twombly Red Sentinel Japanese Maples that are a few years old. I noticed yesterday that they have an infestation and am hoping you ...
Knowledgebase
Pest identification Request #896501
Asked April 06, 2025, 11:33 AM EDT
Hello, we have two Twombly Red Sentinel Japanese Maples that are a few years old. I noticed yesterday that they have an infestation and am hoping you can confirm the bug and best course of effective action. We had aphid issues with potted flowers in the past. So, was initially assuming these are a type of aphid, but the picture closeups don’t look like what I’ve seen previously. However, there is definitely the sticky homeydew present like there typically is with aphids. Can you please look at the attached pics and confirm identification of the pest and best effective course of action? Thank you!
Clackamas County Oregon
Expert Response
Yes! You are correct, these are aphids. Specifically, they are most likely California maple aphid, Periphyllus californiensis, found worldwide attacking Japanese maple. More info here. For management with just two trees, you could try just a high pressure water treatment. Otherwise I would recommend a insecticidal soap spray or a botanical oil. Note that it is early in the season and there will be more natural enemy activity as the growing season progresses so you will likely see predatory insects coming after them. On the other hand, you mostly show nymphs in the photos, so it is a good time to knock back the populations before they really get going.
Ok, thank you for the info. I may have missed it in the info that you linked…in addition to the treatment you mentioned, is there systemic insecticide treatment that you would recommend applying which could be beneficial?
A neonicotinoid such as imidacloprid would give you a systemic effect and long term control, but these products can be very harmful to pollinators when they get into flowering plants and are typically not our first recommendation.
