does this fit your description ?
Thrips
An enlarged picture of the thrip, these insects are smaller than a pinhead
Prevent: Keeping clean habits is the only defense against a thrip infestation. These tiny insects will go unnoticed even by the most cautious grower until they reach damaging levels.
Identify: The thrip is commonly a greenhouse pest. It is difficult for the thrip to reproduce in large quantities outdoors and they must hitchhike into indoor gardens. These little guys are TINY! Thrips can be almost any color, move very quickly and have wings. They can be hard to see individually however detection should not be difficult. Thrips have a tendency to move in herds together, ripping tiny strips off the top of your leaves and drinking juices below. This can deprive plants leaves of chlorophyll so thoroughly they become brittle, dark, and crumble. Tiny black lines present across leaf surface, thats their toilet. The flying thrip can easily infest your garden very quickly if protected from outdoor conditions. The female thrip bores a hole into plant matter and leaves her eggs there in a hole so small you will need a magnifying glass to even know it is there. Apologies, I've been saving the worst for last. In
marijuana the thrip prefers to thrive, eat, shit and reproduce primarily inside buds. Shaking branches will send these pests flying and jumping for other places.
The left leaf is earlier in thrip damage progression, and the right is severe damage. Damage done by thrips to leaves that initially resemble scaling but the damage becomes clear as the thrips progress
Eradicate
Repression: Forced air circulation using powerful enough fans to move air throughout your greenhouse or growroom can keep the thrip from being able to hang on or move. Regular misting of water will flood the thrips on the leaves and slow their travel, reproduction, and ability to damage your plant. Sticky traps will help, however the thrip is happy eating in the same area for its entire life cycle. Low migration reduces effectiveness of sticky traps.
Predators: Nearly any predatory mite is effective in combating thrips. Parasitic wasps may also be used, however the sheer numbers of thrips limits their ability.
Manual Removal: You might be able to see herds of the tiny specks moving around your plant, crushing these will reduce their numbers of course but is not effective overall.
Spray: Pyrethrum or insecticidal soap sprayed 2-4 times at 5-10 day intervals will nuke thrips back to the stone age