m0useanswered grow question 2 years ago They look like larva or pupas of some sort.
Add in some BT into your res and it should help clear out the bugs, it will kill them and start to put and end to the life cycle of the pests.
I would also install yellow sticky traps to see if you can find any flying bugs. I'd also look on the roots and see if anything is infesting them like root aphids.
Need more info and clear pics of the things.
Good Luck!