Answer: It's hard to say for sure, but it does sound like a scale insect. I would begin by gently scraping them off, one by one. It's time consuming, but because their "shells" render many insecticides ineffective, it's a good way to control adults. A weekly spray of horticultural oil (mixed according to the package directions) is effective against the young ones, since they haven't yet developed the hard shell. Be sure to spray the undersides of the leaves, since this is where they congregate.
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