PlantHoarder

I have been fortunate in that is one area this season at least that has not been attacked.

There are possible solutions that are not organic but could be more effective against them. The little SOB's like to live underneath the leaves until the leaf curls inward and then they nest inside it.

Mixture of Neem oil and soap is one potential avenue if you want to stay semi-organic friendly. the other option its to mix an insecticidal solution with some type of natural oil (or neem oil) oil and manually brush it on, I haven't tried this one yet so i'm just spitballing.

This is most devastating to young plants, but if a tree is healthy enough to begin with it usually grows enough that thrips and mites are not a significant threat.
I grow a lot in my not very large yard and spider mites, as well as thrips are an ever present seasonal annoyance for my outdoor flora.

It is likely they are infesting neighboring plants, if you find any infested leaves burn them, don't just discard. They will overwinter in the nests they create for themselves and (and sometimes the dirt around it, then) re-emerge the next season.