I bet is is scale.  turned my hands green squishing the bastards by running my fingers up and down the stems.  bought a bag of ladybugs at Sun Harbor.  Helped a bit.  I tried neem, didn't work that great.  Did the dishsoap with cayenne and lemongrass. That killed more. I don't know where they come from, but they continue to return.  I didn't do coffee grounds on the crotons.  Then they went ballistic on my firebushes.  I threw in the towel and sprayed them with talstar.  All dead. I don't know how long talstar lasts, but I did it when nothing was flowering. hate to use that stuff.