Tea scale (Fiorinia theae) is a common insect pest of camellias. It causes the tops of leaves to appear blotchy yellow and the undersides to be coated in a white fluff. The female scale is dark in color - dark brown or dark gray to almost black. Male scales are snow white. When a heavy scale population is present, the undersides of leaves take on a cottony appearance. It is difficult to control, so it's best to inspect plants on a regular basis and treat when scale is first observed. Spray the plants with an oil spray during the late winter/early spring, just after they finish blooming and before they start growing. A systemic insecticide or a summer-weight oil can be used during the growing season. Contact your local Extension office for specific insecticide recommendations.