Young Maple infested with something on bark - Ask Extension
What is this on the bark of my young maples? How should I treat it?
Knowledgebase
Young Maple infested with something on bark #927359
Asked April 02, 2026, 2:00 PM EDT
What is this on the bark of my young maples? How should I treat it?
Queen Anne's County Maryland
Expert Response
That is Japanese maple scale on the bark of your maples. This armored scale is hard to control due to its multiple overlapping generations, extended crawler emergence periods, and wide host plant range. You will need to monitor the scale closely and time any control measures with crawler emergence. Detailed recommendations on control measures can be found here https://extension.umd.edu/resource/introduction-scale-insects/
You will most likely need to make more than one treatment application during the growing season in order to control this scale. You may also seek out a certified arborist who can do the monitoring and control for you.
Marie
