bess,
I am not an expert on camellias, although I do have them.
I planted 5 pittosporums a couple years ago in the front of my house for privacy.
After a couple years, this fall in fact, i noticed they are getting awful scale all over them.
This is what I did, and it helped.
I read that scale and ants go hand in hand.
I checked the area (about 2 months ago) and there were the ants. A big ants nest, i didn't even notice it, about 2 feet from the first bush, and then I noticed more ants and nestss around the other bushes. The nests were hard to see in the tall grass.
I put Amdro all around the bushes and on the nests.
THen I read that if you plant a flowering plant close by the tree or shrub that is prone to scale, it will attract insects to eat the scale. Especially wasps, they eat scale.
The ants are gone, some of the scale is gone, but next spring i will definately apply the Amdro again, and also in the summer.
Hopes this helps a little.
Amdro is easy to find at HD, so try it this spring, and see if mabey this helps you.
My favorite camellia is out back under a pine tree, and she has never had scale, but she is surrounded by flowers all summer and there are multiple wasps that probably take care of her.

Are you trying to leaving bare trunks so the old ones grow in tree form? Can you post pictures of one of these old ones? You could highlight the area where you want to remove branches by editing the picture of using some type of visible yellow tape placed on the shrub and facing the camera.

What I would advise is spraying with one of two oil sprays. Horticultural oil spray is generally done for spring summer spraying , Dormant oil sprays are usually done in fall/winter. You should be able to find these at a good nursery I am not sure if the box stores sell them I got mine at the co-op. They can be found under several trade names. They are very safe. The brand I bought is High Yield a generic name. My cousin has a bottle that is labeled volck. You must do a thorough job of the spraying, targeting the underside of the leaves. What it does is smother the insect so it can't breath which of course will kill it. Hope this helps you. Maybe someone else will post another answer. Years ago cygon 2e a systemic was used. I don't know if this is even available anymore.
James in Florida

If you search the forum for "bayer" there are some good responses on this subject.

Granular Merit (a granular form of imidacloprid) gives me pretty good control of scale on camellias.

We get the Merit in 30-pound bags. The label seems mainly oriented to lawn applications. Naturally, if you decide to use this product, you should read the label.

Personally, I sprinkle about a half-cup around a 4 to 6' bush. I'm not sure about the official recommendation.

We apply it in late March and a second application in late July.

It also helps to remove twiggy growth from the inside of the bush. Lots of leaves and twigs in the middle of the bush is an invitation to scale.

Another thing I do when I find scale on just a few leaves is to clip off the leaves, or if the branch is small, I'll trim it off.

Horticultural oil sprays are good, however it's important to get good coverage on the undersides of the leaves. This is not always easy to do, especially if the camellias are large.

In emergency cases, I have used a different systemic, Safari.

I have a love-hate relationship with all of these pesticides. There are definite environmental concerns, especially with Safari. I tend a large estate garden mainly by myself, so I look for efficient solutions. I justify my use of Merit by telling myself that I'm using it on a relatively small area an fewer than 500 plants.

The best option is to use an all seasons horticultural oil. But many people (and sadly to say) and most chemical applicator companies spray "at it" and not "on it". We spray camellias professionally and we only use horticultural oil that has paraffin in it's ingredients. The trick is to get a thorough application - which means you have to saturate the plant until you see no white, this means under the leaves as well as on top. You can't do it with a sprayer either - the best tool is an ortho hose-on sprayer. This will force the oil into the scale. Pump up sprayers are inadequate. On heavy infestations you will have to have several repeat applications. Oil works through suffocation. Once under control, then you can spray about 2-3 times a year and wha-la, no scale in no time at all. We have completely eradicated very severe infestations successfully.

Here is a link that might be useful: Tea Scale Spraying Guide

This post was edited by camelliagardener on Tue, Nov 19, 13 at 8:21

I agree with those recommending the horticultural oil. I would rather smother the scale than try to poison it.

If it just seems overwhelming to treat 6 large plants, you may want to prune some of the branches with the worst leaves & work on what's left. Less radical than chopping down to the ground, and a bit easier than completely treating unpruned plants.

Good luck, and Happy Thanksgiving!

Tea scale very difficult to control. Use horticultural oil for best control

This post was edited by SavannahNana on Sun, Dec 29, 13 at 5:42