I can tell you how to prevent them.
But once infested, that late in the game, there is little hope.
Hadda scrap my grow, scrub every surface, dump my coco, and start fresh.

Now, I keep the flyers from laying eggs with dryer strips on the soil surface and treat seedlings with Imid. to kill the sap-sucking spawn.

If you do find a remedy, please post it.

Aloha,
Weezard