This summer we have seen many Magnolias affected by scale. You will notice mold-blackened leaves (from the honeydew) and white scale on the stems. There many be many bees, and ants too, attracted by the honeydew. Treatment includes an oil/insecticide mix ASAP, followed by a fall dormant oil. Next spring the tree should get a high rate dose of imidacloprid. If left untreated, the trees will likely die.  For more information contact consulting@chippersinc.com.