Question
The sago palm in my front yard was flourishing.  It is in partial shade.  In the past 2 weeks I noticed that several of the stems and leaves are dying and turning brown.  Also some of the leaves have a black film growing on them.  What would be causing this and is there anything I can do to save my sago?

Answer
Dear Renee, You probably have a scale insect that is growing on your sago.  You will probably see some white, brown, or black bumps that are on the fronds.  Scale is an unmoving insect that lives under the hard outer shell.  Or you could have mealybugs which are fuzzy and white and move very slowly; it is a slow moving form of scale.  Anyway, scale, aphids, or trees overhanging the sago dropping a variety of substances (sap, pollen, bug residues) are the major causes for your sago getting the black soot.  At any rate, the black film is a soot covering and smothering the leaves so they can't process the sunlight, and that's why they turn brown.  Now, here is the easy way to fix it.  Spray the sago with horticultural oil (SunSpray is my favorite) both on top and under the leaves.  Spray to the point that the plant drips.  Wait several hours on a warm day and the black soot will begin to flake off.  You will need to spray several times to get rid of it all, but it will come off.  You can spray every few days to get it off faster.  Please write back if you need further assistance.  Good luck, Melissa