What to do about cottony cushion scale, a common pest of citrus

Q. What are these weird white things on my citrus trees? They don’t seem like they’re moving, but they sure do attract ants!
Cottony cushion scale is a common pest of citrus, but can also infest other outdoor woody plants, particularly nandina and pittosporum. Usually, they can be found on new twiggy growth at the base of leaf petioles. The scale itself is rather small and golden brown in color. What you notice is the large egg sac she carries around like a white pleated oversized ba