Well, I presume most insects are a threat. I've been unable to identify this little beast, hopefully someone here can tell me how nasty it will be. I am seeing them only on my small Waterfall maple so far, but will be doing a thorough inspection of all of my trees later today. What can I do to remove them, and at this early growth stage will it be safe to treat it at all? I've sent these photos to a good friend (Eastwood Nurseries), but thought more opinions may be warranted. Thanks in advance.
Most insects are harmless, some are a threat, and some are beneficial. Looks like an aphid there, which is a minor pest. Hand-squish them if you like, or leave them for birds to eat.
I would brown aphid - track down some lady bugs ( I have ordered them on line several times) and release them on your plant(s) Problem solved! Best Regards, CSL