Question
I live in S. FL and have a long hedge of cocoa plum.  It stand opposite a leafy shrub that is prone to white fly.  The leaves show the tell-tale black mold but the cocoa plums' stems (small "trunks") are covered in small black bumps (they look like ground pepper corns when removed from the branches). I would like to identify this pest and make my own "chemical -free" treatment to eradicate this problem. Please help!  Thank you!

Answer
This sounds like a scale insect--take your finger nail and squash the "bump" and if a liquid comes out it is an insect. The scales live under these bumps and suck the juice from the plant. They will also produce honeydew and the sooty mold will grow on this sugar substance. To treat the scale you need to use a systemic insecticide. A good one is Bayer Advanced Tree and Shrub insect control. This is applied to the soil under the tree and the roots pick it up moving it to the branches and leaves and when the scale sucks the juices they are killed. Control the insect and the sooty mold will wash off with rains. Here is a link to this product and it your local nursery/garden type store should have it.
http://www.bayeradvanced.com/product/Tree-Shrub-Insect-Control/super-concentrate...