Badly infested with scale and possibly with mealy bugs. If you have warm temps, I would take it outside and spray with malathion. It's not what most folks like to use, but it works.

I'd caution against using hardcore pesticides yet. A few sprays of horticultural/neem oil will solve the problem without having to resort to stuff that requires special handling.

Between oils and organophosphates, there are also other solutions..

Nik, what are the other solutions?

There is physical removal....then horticultural oils... then systemic insecticides like imidacloprid, then a combination of all of those... but last and most damaging are broad spectrum insecticides like Malathion that kill not only your particular pest; but also all of your beneficial insects that work for you for free

I agree with johnmerr. Why use the nuclear option (Malathion) when other options exist? I would only use Malathion as a last resort.

Neonicotinoids like imidacloprid are useless against cottony cushion scale and some other scale. In fact, it is counter indicated since it affects its main biological control. Over here, pyriproxifen and spirotetramat are recommended together with oils depending on the type of scale. These are growth inhibitors and not knock down insecticides. If going for the organophosphates it is better to use chlorpyrifos but I know it is not available for home and garden use in the US.

Thanks everyone for your advice. I rubbed each leaf and stem with alcohol/water solution, picked every single bug that I could see, and sprayed with a neem oil product. Will continue to watch for reinfestation but it and the adjacent mexican lime already look better. Thanks again!

I would recommend you continue to wipe the leaves with an alcohol solution and then spray with HO/neem on a regular basis. Based on those pictures, you had a bad infestation. There are likely bugs that you missed the first time around. Weekly or by weekly cleanings will keep it from getting bad again. They have a way of sneaking back up on you before you know it.