What is the green sap on the bark of a fruitless magnolia tree. The tree has a lot of green on top of the bark. We know it already as water seeping into the tree Trunk and causing sap seeping out white fungus.
While the name and appearance may suggest a fungal infection, it’s actually an insect that feeds off the trees. It’s a common mix-up because the mature female insects don’t really move around—they’re essentially immobile lumps that just stay put on the branches. Similarly to aphids, they suck out the tree sap and excrete “honeydew,” a sticky substance that ends up coating our plants, homes, and vehicles, and can end up becoming a breeding ground for unsightly fungi, like sooty mold. It’s the largest soft scale insect, reaching up to 1⁄2-inch long at full maturity. A significant infestation can drain trees of a considerable amount of sap, leading to yellow leaves, dying branches, stunted growth, and even death of the tree.