It sounds like it could be Cottony Maple Scale. Silver maples are the preferred host. Here is information from the University of Minnesota on Cottony Maple Scale:
http://www.extension.umn.edu/garden/diagnose/plant/deciduous/maple/leavessticky.html
http://www.extension.umn.edu/garden/insects/find/scales/soft-scales-deciduous/index.html

Would I need to use something like Tree and Shrub Insect Control by Bonide and apply in the fall only?

I don't use chemicals in my gardens, so I am unfamiliar with that particular product. If you do not want to use chemicals, I would try managing the problem by waiting to see if natural enemies will take care of the problem. Another solution is to apply a horticultural oil or insecticidal soap in the fall to try to smother overwintering females. If the problem is quite bad and you are not adverse to using chemicals then scales can also be effectively managed by systemic treatments of imidacloprid applied in the fall.  If you have purchased Tree & Shrub Insect Control by Bonide already or are planning on purchasing it, check the bottle to see if it has imidacloprid as the ingredient and if it does, apply it in the fall.