Tiny webs sure sounds like them. And boy do they love Citrus. With a loupe or hand lens you should be able to see them moving along the little web strands, and on the undersides of leaves. Or try tapping a suspected leaf over a piece of white paper; you should see tiny specks not much bigger than dust slowly moving around. AFA spraying there's plenty of info out there. One site suggests adding horticultural oil to the soapy mix. Just make sure you get the leaf undersides really well. I've tried spraying my indoor plants time & time again but they always seem to find their way back eventually. I heard ladybugs will eat mites, but I imagine their preference is for insects (mites are arachnids, maybe explains why the pyrethrin didn't work?). I've had some success with predator mites, although IIRC a second application is usually needed.

John Why do you kill spiders. In my area the average house has over 60 brown recluse spider. Any spider that is not a brown recluse will eat a brown recluse or any other insect it can find. Brown recluses feed on dead and injured insects. Any other spider eats the insect before they die or become week and thus starve the brown recluse. This greatly reduces the chance of a brown recluse bite. I could understand your position on spiders if the Brazilian Wandering Spiders live in your area. I would like to have a Huntsman or Goliath bird eating spider in my house to take care of my mice. Right now I have a couple of snake slithering freely though my hose and the mice really dropped their numbers

Oh whew...I am so relieved to read that nobody thinks they are spider mite webs. Whew, whew!! Is there some definitive way to determine mite webs vs spider webs? Thanks TJ. You are right. And I haven't sprayed a thing, good or bad, in the last 15 years with the mentality of "come what may" but this yard has been trying. I have never seen so many good and bad bugs in my life...and in the last month resorted to BT to kill the hornworms that are decimating my tomatoes and since I'm spraying anyway, I bought the neem which I'd read up on here. It appeared to be pretty innocuous overall, so that I used along one fence where most of my succulents live in light shade and dappled sun--that's the area where both of these photos were taken. None of it was sprayed on my edible or flowering plants, as I read that neem can damage blossoms... The only thing I have consistently used except when I lived in SF was snail bait and they seem to be having quite the blast anyway this year. Jean, we sure do! I can't confirm my neighbor ID'd what she saw correctly but upon hearing that and about two minutes before I ordered neem, lol, I did google it and Japanese Beetles were spotted in the Sacramento area, right above me, per the CA Dept of Ag. I only read one article but that was close enough for me! Ken, my spiders are year round, I'm afraid. January has much less than the other months but there is no month where I can't find spiders crawling on my plants or webbing here and there. Come spring, there's virtually no plant I can't find a spider on or at least evidence of some spider having been on it. That said, I still find it really bizarre that at this yard, for the first time ever in my gardening life, I have not seen ONE aphid. Spiders are not predators of aphids, are they? I've never seen a ladybug here either..probably because there are no aphids. Not complaining but I find it so bizarre! Thanks again, folks!

Do not use soapy water - I know it is often recommended, but it dissolves wax on the leaves...the only soap to be used on plants should be true vegetable-based Castile soap (olive oil based). I do not have experience with neem oil, so can't comment. Lots of marks appear to be oedema (the hard, black bumps), even the bigger dry-looking patches. That happens when plant cant transpire all the water received. Other is possibility of powdery mildew, encouraged by high humidity. What kind of soil/mix is it potted in? Where is this plant kept? How much sunlight is it receiving? Even if you say it dropped lots of leaves, it looks quite etiolated - spaces between internodes are too big. That suggest not enough light. I would also suggest potting plants higher in the pot - the soil level should be higher. That will also help with soil drying up faster and general air circulation that is also important for succulents.