Q. My live oak tree foliage is covered with fluffy growth that looks like a fungus. The tree is only a few years old and 10 feet tall. Any idea what the fungus might be, and how it should be treated?
A. From the way you describe it, I believe it is probably mealybugs, a form of aphids that suck the plant juices while protected by that calcium coating that looks like fungus. Mealybugs are most common on tropical hibiscus. On a small plant, you can do a fair job of controlling the mealybugs by spraying them off with water pressure or hand removing them. Acephate and other systemic insecticides work sometimes when sprayed on the plant.