Can we see some close up photos of the leaves with the insects on them? There are both armored and soft scale but the armored is much harder to treat. A systemic may be the best approach.

The black powder stuff is probably sooty mold, a fungus that grows on the honeydew excreted by sucking insects like scale. It is harmless to the plant itself unless thick enough to cover a majority of the foliage when it can then interfere with photosynthesis.

Are these close enough?

I don't think it is either spider mites or whiteflies. Spider mites are so tiny as to be almost microscopic and hard to see with the naked eye. And they don't produce honeydew so cannot be the source of the sooty mold.

There is a possibility of it being whiteflies but there is no sign of any adults. That could be due to them flying off when the photos were taken - Socks, maybe you can confirm if this happened. But the creatures left behind that do show in the photos appear to be much too large for a juvenile stage of whitefly. Their eggs and larvae are also tiny and hard to see without magnification. Whitefly do produce honeydew, though.

I am pretty sure that is a type of soft shell scale, which one in particular, I can't say. They can be very flat or develop a convex shape as they mature. If you enlarge the first detail photo, you can see both forms. And soft scale often aligns along the leaf vein and petiole (see second detail photo) as that is the juiciest, most succulent portion of the leaf. Soft scale doesn't move or not so you'd notice but can be easily scraped off using your fingernail. And they are a prodigious producer of honeydew!

Controlling a scale infestation is not easy and can take several treatments. Using alcohol to wipe down the foliage works well for houseplants but is tedious when dealing with larger outdoor ornamentals. Per UC IPM guidelines, hosing down the plant with a strong spray of water both from above and below is the first line of defense but unlikely to be very effective against an established infestation. Horticultural oil is the next option - difficult to apply completely and generally requires multiple applications. Spray insecticides come next but have the same drawbacks as using hort oil and can be quite toxic to humans as well as to pollinators or other garden beneficials.

Systemics are a practical alternative. Most can be applied as a soil drench and are then taken up into the plant tissues. They are pretty much limited to the target organism or other sucking insects so relatively safe to apply. But there will be a time lag between application and control - that absorption by the plant does not happen immediately.

I would strongly suggest you take several samples showing the insects and the leaf damage into your county extension office for an ID confirmation and their recommendations for best control methods.

Thank you both for your thoughtful, helpful replies. No, no white flies seen.

I think what I'll do is get into the bush and thin it out, cutting off the worst affected branches, getting it away a bit from the eugenia behind it, basically cleaning up that area and the fallen debris back there. The bush has been there for years, and I think it will recover ok as far as growth is concerned. Then I can hit it with a strong spray from the hose to clean it up a little and consider what to do next. If I remove enough, maybe alcohol swabbing will be doable. I'm really not interested in spray or systemic. Thanks again!

Just to wrap things up since you posters were so nice to help me. I pruned the bush down to about 1/4 of its size and lifted up the eugenia behind it to give more air circulation. I cleaned up excess leaf litter, donned some plastic gloves and a spray bottle of alcohol and massaged the remaining leaves. front and back. Then I gave it a handful of compost, worm castings and fertilizer and good hard water spray and drink of water. I'll keep an eye on it.

👍👍

scale is a tough pest to beat but you can do it. Try oil and lemon scented dish soap. If you dont want to use systemic poison it will be a prolonged fight. try to get as many visible bugs off as you can and keep treating the leaves to get the baby ones.

OK, thanks. I've been working on it a bit every few days.