Your tree is not infected with anything, it may have had somethong at some point but I wouldn’t go spraying any of my trees rigorously after having it for 1.5 weeks. That’s barely enough time to observe any change other than a little wilting from the transplant to your new pot. Mother Nature has a way of taking care of any bug infestations or mold problems naturally out here in the desert. Lady bugs have just started showing up, praying mantis are just starting to hatch, those 2 bugs alone will take care of any potential bug problem you may have. If it were mold on the leaves that will go away with the coming heat in the next few weeks when your tree starts to flush with new growth. But if you arbitrarily start spraying your tree because you think you see something you could be doing more harm than good. I’d relax a little, observe your tree and take some time to let it settle in. Just my advice.

Evan

Thank you Evan. I do get carried away! COVID-19 has only made this worse because now that I am working from home I can frequently check on my young projects.

Knowing that a new home stresses these trees out, I was really worried what an infection would do on top of that. But I will heed your advice and just ride it out.

it’s super easy to kill sooty mold....

How to get rid of sooty mold on plants

The black residue on your tree is sooty mold. Sooty mold is produced on the honeydue excreated by insects. It is rather easy to remove with a hose or just using a cloth. The main problem is that the black covering reduces the plants abibity to manufacture food by photosynthesis. .You can find out a lot of additional information about sooty mosd on the Enternet.

Thank you all. This being my first exposure to the issue, I was looking for confirmation that it was sooty mold, and not something else that a novice gardener like myself might miss. Consensus is it is sooty mold. I will let good old fashioned Phoenix sun dry that stuff out, and maybe give it a little extra help with some soapy water. I'll also be vigilant for possible underlying pest problem.

Sooty mold is impervious to sun (grows just as well in sun or shade as long as honeydew is present) so if you want to remove it you will need to wash it off.

Thanks Dave, I haven't seen any bugs. It looks like scale can be really hard to spot because they are so small, but I will keep checking.

Good to know gardengal!

I cleaned the soot off, came off easily with soapy water. I found these spots on nearby and affected leaves. They almost look like burn marks. I assume that is where the offending bugs latched on. Would these be signs of scale, or would other potential offending bugs (white fly, aphids) also leave such marks? I don’t see any signs of life anymore, just curious what pest inhabited my tree, if it’s possible to know such things.

I also found a couple of these spots on a few leaves. Look like the leaves had bleach spilled on them. Would this be a nutritional deficit, or just “character”?

Thanks in advance to anyone who is still reading this post and sharing their experience with this overeager novice.

I don't think those dry patches on the leaves are anything to worry about. Maybe sun burn.

Actively feeding scale (or aphids) would first manifest themselves with sticky droplets on some of the leaves. This is the honeydew that attracts sooty mold spores.

I believe I spy some scale insects in the last image of your first grouping. On the stem. I'm guessing that wherever you purchased the plant from tried to control an outbreak and ended up shipping their customers some black sooty mold residue and a few leftover insects.

If caused by scale, look for green to brown flattened or domed discs (the mature scale insect) firmly attached to the undersurface of where the leaf meets the petiole (leaf stem) on either side of the mid-rib or all along the mid-rib. This seems to be the first place they appear. You can remove them with your fingernail.