Nice plats mate.
Most people tell me they are harmless and i witnessed it with my own eyes.
I saw perfectly good looking plants that were infested with those white devils.
My guess is that things are fine if they have enough organic matter to feed on.
If they don't they start feeding on what lies around (roots).
This would match the information i found about Onychiuridae that cause problems to beetroot growers in Europe.The data i found indicates they feed on tubers.
I only use coco for veg in airpots and then transplant to hydroton.
My clones died and older veging plants had top curving leaves and slow growth plus the harvest was diminished.
So i guess something went wrong.