Hi there, I have a Japanese maple that has been happily living on my NE facing deck for about 10 years. My wife and I just love this tree! The color changes throughout the year are amazing even though it only receives about an hour of direct sunlight once every early morning and late day/evening in the spring/summer. I’ve had only just few problems over the years with this tree such as a few Aphid outbreaks and forgetting to water the odd time. Anyhow, this year I’ve noticed for the first time something eating the leaves. Upon further examination, some of the leaves are suck together by something silky, web like. Pulling apart these stuck leaves reveals small, light green, inch worm like caterpillars that are about 1 cm long. I’ve gone through the tree in a quick search, unraveling stuck leaves plucking the pests out and destroying them. Anyone know what they are and should I be concerned? Thanks.