Contact your local County Extension Office for advice on dealing with nuisance wildlife. Their contact info is:
Sarasota County Extension - 6700 Clark Road, Twin Lakes Park, Sarasota, FL 34241-9328
Phone: (941) 861-5000 (Ask for the Sarasota County Extension)
The spots on your magnolia leaves could be insects such as scale or aphids or mealybugs, or they may be water residue. Take some of the leaves in a ziplock bag to the Extension office to find out what the spots are.
The green stuff on your oaks is one or more of several types of lichen. These don't harm the plant and nothing need be done about them.
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