Can scale be cured?
I have both a lawn and tree/shrub service. They have treated select shrubs with landscape Horticultural Oil. They say the application works to control scale, as well as the eggs of some other insect & mite pests. My question is: Isn't there anything to cure the scale?
In general insect pests are host specific. Scale insects belong to a large group of sucking insects and there are two types, armored and soft. You have to identify the plant and the type of scale insect before a control can be recommended. Often these insects are attracted to stressed plants and are difficult to control. Here is some information on scale http://extension.umd.edu/hgic/plants/armored-hard-scale-trees-and-shrubs
If your shrubs are growing well and the pest problems are under control, then you do not need to spray. It may be helpful to view our publication "IPM - A Common Sense Approach to Managing Your Landscape."http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG62%20IPM%20A%20Com...
You should meet with your landscape company and have them explain what they are spraying and why. You can also attach photos of the plants in question and affected foliage.