For sure looks like some sort of maggot in that picture. I suspect they aren't plant material only judging by how they are inconsistently on/attached to the leaves.
i think it was just one of the stages they go through.. i took that snip from this video...
Glad you are mite free. Did the sulfur have any impact on the plant you put it on?
no, i don't think i gave them enough time though, it was only on there less than a week. i put some on a couple soil plants but it hasn't stopped it from looking bad.
i'm gonna keep looking for sure... honestly i'll probably never stop looking now..at least for a few months i'll still be on high guard. i've never had russet mites before and i am told they are the toughest to battle.
My hypothesis is algae in your rainwater tank. Or organic material in general. I'll explain more when I have a minute.
oh by all means pothesis on with this theory!! i know for a fact 100% i had algae in that water, not even a doubt. i almost posted a pic for you but never did. we were already moving forward with treating it and thought i'd be beating a dead horse with problems..
this is a before and after shot of that barrel of water, you can see the green...

I'm guessing that is a shot from the interwebs of adult HR Mites. Hopefully not #5's plants. I think this place would be on fire if he saw that.
correct, not my photo.. i tried to get shots through my little scope with the camera but it looked fish eyed goofy! haha
i told you if i see crawly shit i'm sellin!!!! the neighbors place down the road just went for $650K and they only have half the land i have!!! hahaha
and if i see crawly shit in the water i'm calling sigourney weaver!!!!