White fibrous balls

I have found some small, head of a pin, white fibrous “balls” under some leaves.
Under a microscope they have tons of fibers some black, mostly white. They seems to be harmless since there is no apparent damage where they are located.
Had some last year too but didn’t seem to hurt anything.
Has anyone seen these?
Is there cause for concern?
Sorry I have no way to take a pic.

Sounds like bugs maybe spider mites
With out a picture will be hard to tell exactly what type of bug

I understand and agree, a pic is worth a thousand.

You’ll want to inspect the leaves frequently
Good grade de can help get rid of pests or been oil used in veg only

If you can upload a picture I’m sure we can help you out more @Tarzan