Cottony Cushion Scale

 

The name fairly well describes this insect. Young scales of this species remain mobile until about half-grown. Then they settle down, and the female grows into a white, cushion-shaped mass, which may be surrounded by fuzzy, white strands (cotton). The female body will be filled with eggs and young as she matures. Often cottony cushion scale is naturally controlled by Vedalia beetles. Vedalia beetles are small (3/16 to ¼ inch long), black with orange spots lady beetles, which were introduced to California from Australia many years ago, specifically to control this scale. Therefore, if your bush is only lightly infested, I suggest no treatment. You will need to examine the bush periodically to see if the scale population is worse, status quo or declining. If the population is going up, you may wish to augment the existing Vedalia population with more beetles, which can be obtained from a predator supply company. Cottony cushion scale can also be controlled with summer oil. If you spray, coverage is important. Make sure all plant surfaces are wet. No matter which control procedure you use for the scale, attention should also be paid to ant control. Ants protect and shepherd scale insects. They will drive away Vedalia beetles from the scale colony, preventing them from feeding on the scales. Ants will also redistribute scales to new, young twigs and leaves where they will establish new scale colonies. There are physical barriers, baits, granules, and sprays that can be used to control ants.