Hard to say from the photos. Looks to be something scale-like in appearance if not a type of scale. Not all scale are round. I have cottony cushion scale in my yard and they look nothing like the round armored scale. Without knowing where you are in the US,
this page has good info about the types of scale found in California and likely elsewhere in the US, though your area may have species not included if you're in a wildly different part of the country. From there you should be able to figure out what you have, or what to lookup online to figure it out.
I'll leave the treatment advice to people that grow these in case they can't tolerate some of the regularly suggested products.