Yea so spider mites (two spotted and red) are crawly, web-making little buggers that, like russet mites, experience an accelerated life cycle with higher temps (above 78 things get faster and faster, probably peaking around 95). They look like little mini ticks (but with white/brown bodies) and their eggs are easy to see, and the baby spider mites look like little teeny tiny white versions of the adults, but move a bit differently. HEck heres some pictures:
Red
View attachment 2205179
Two Spotted
View attachment 2205180
w/eggs
Spider mite damage (early) on a plant looks actually a lot like the brown (egg) spots I outlined one can ID in Russet mite infestation stage 1, but the spider mite damage will almost always show like this:
View attachment 2205183
not brown but yellow peppered spots all over the leaves which they are feeding on. For the russets you will only see such a small amount of damage if you have a very small population of babies. Otherwise there are so many of them that there will be rusting EVERYWHERE (older leaves, as the rusting generally shows more as the fed-upon leaf grows. Also in this stage, it is not adequate to look at these rusted leaves to confirm/disconfirm RM presence, as they have long since migrated to more bountiful parts of the plant. Also as mentioned and clearly visible in the OPs pictures on the first page of this here thread, russet mites are quite a bit smaller, I'd say the adults are a tiny bit longer than spider mite babies but about half as thick, don't quote me on it. There are some interesting anatomical drawings of russet mites from papers from the 70's if you sift through the google results for 'hemp russet mite' or 'aculops cannabicola' you should come up with them. Here is a pretty grisly picture of a close up of a terminal phase plant:
First a pic w/o magnification:
(pretty sure the next one is this same leaf stem just zoomed in)
From my experience this is about a 30-50x picture and you are mostly looking at babies here. I find the adults are more orange/brown colored and like I have said, they migrate to new growth/windy tops pretty readily when the population levels get this high. Also I assure you the plant that has em this bad is dying quickly
I mentioned the orange/bronze color you see when they overtake the new growths or an injury location, I found a picture that looks similar to this(but zoomed in enough you can make out the mites):
(RIU wouldn't let me post it probably because of how it is stored at ICmag, just click the link)
https://www.icmag.com/ic/picture.php?albumid=26282&pictureid=800832
THats all for now, peace (more pics added in edit, yo welcome!)
MPP