When I was outside last month making my first spring pass in the garden I noticed a row of false hollies had leaves all turning yellow and brown. When you see yellow leaves on a plant the very first thing you should do is flip the leaves over and look at the underside. When I flipped the leaves over I found scale. Neem or orange oils are the preferred choices and you can find them at most nurseries. I use orange oil, but in a pinch any oil you have hanging around the kitchen will do just fine. Spray the bottom of the leaves thoroughly.
If only a small part of a plant is effected, prune off that branch and spray the underside of remaining leaves with oil. These plants are totally covered. So if the spray does not work after two weekly applications, I’ll cut them back to the ground and let them start over.
Tea scale was first discovered on tea plants in the early 1900s. Hollies, camellias, tea, olive and citrus plants are all known to be victims. The life cycle is between 45 to 65 days. We can get them year round here in Houston as well as in other warm climate areas. Usually they show up in the spring.
If you have constant problems with scale in your garden you might also consider a systematic pesticide. These are absorbed by the plant through the roots and deliver toxins to the scale. I don’t use systematic pesticides in my garden, but if you are constantly fighting scale you should consider them. They are available at your local plant supply place as well. ( see Control of tea scale using root absorbing systematic insecticides )
About the only good thing you can say about scale is that is doesn’t move. So you know where to find it when you come back with another round of toxins. Scale does have a crawler stage early on when it is first hatched. Once it finds a good location it settles in and forms a hard shell over itself. Almost all the scale you see are female.