You can still apply summer oil in Louisiana now. You can also mix liquid Sevin in the mixture if you would like. Treatment for all scale insects is basically the same.
As a shameless plug, visit
www.lsuagcenter.com and look at the top for the tap marked publications. We have 3 separate control guides for Louisiana: insect, disease, and weeds. These are all in PDF format and are FREE downloads. You can download the section you need or the entire publication.
Just a FYI from your friendly LSU AgCenter Forestry and Wildlife Agent.
Robbie aka Big Hutch