Definitely spider mites in my opinion

The roots may have sucked out the nutrients from the soil. If the roots are sparse no problem, soil is probably fine. If there are a lot of roots in that soil consider amending the soil with some compost or nutrient rich material since the soil may have been depleted.

There are sources of the active ingredient glyphosate that aren't monsanto produced. There are even surfactant-less mixes so you can add your own