Scale Insects on Bay, Myrtle and Aloe

Could you tell me about a pest that sprays a sticky film on plant leaves (and the surrounding furniture and floors!). It is followed by the appearance of flat, brownish creatures on the tops and undersides of the leaves. It has plagued my bay laurel tree, Greek myrtle and aloe plants for quite some time. I have never actually observed the creators of the sticky substance. I'd really appreciate any information you could give me about this pest, its effect on plants, and how to control it.

You have the much dreaded scale insect. This pest has a hard, inpenetrable shell which is hard to control using organic methods. If you use a razor blade you can lift the 1-2 mm (1/16 to 1/8 inch) shells to expose the live insects underneath.
In heavy infestations on large plants the only solution is to destroy plants. In the United States a highly refined oil spray is available which is effective on scale. Repeat applications, preferably by dipping the whole plant (except for the soil) in a oil spray mix, will work. Soap spray does not work well, except perhaps for a short period in summer when the insect is mobile.