What kind of shrub, Stanley? Can you post a picture of it, plus a closeup of the problem?

If your plant is a type of pine, then this could be honeydew that is secreted from the insect called the Pine scale, check for signs of this insect, over here i use Provado bugclear which is very effective, you should have something similar over in the states.

I think the same product in the States is Bayer Tree and Shrub Systemic Insect Killer. Active ingredient is imidacloprid, and several other brands have essentially the same thing now.