Dry seeds sometimes are subject to weevils laying their eggs in them. The eggs hatch and the larvae eat the seed. Eggs and larvae can be killed by freezing for four days at zero degrees. Al

Does it destroy the flowers before they open up? I have seen some type of larva in my coneflowers that burrow and I think destroy the seeds but they don't seem to ruin the flowers so I have left them alone. I suspect the finches eat the worms along with the seeds. I do still get a few seeds and volunteers. You may have a different pest than I do though. I am having a similar dilemma with my salvia plants. There is a moth larva that destroys the buds before the flowers open up so I get very few blooms. I planted the salvia for hummingbirds and butterflies so I don't want to spray pesticide on them and I'm at a loss on what to do. So far I've left those alone too. It's ruining my 'Black and Blue' and others.

do you see any damage to the plant ??? if not.. whats the problem ...??? you dont have to kill everything in the pot ...if its not a houseplant ... if you repotted.. why didnt you just fleck them off ... they could just be a byproduct of wood in your media.. and the over watering... are you positive on that ID.. or are you just saying they looked sorta like these??? you really should not go dabbling in using chemicals .. until you properly Id the problem ... e.g. these could be insects.. and mites are not insects.. so using the goo for mites.. might not be a proper use ... ken https://www.google.com/search?q=mites+are+not+insects&ie=utf-8&oe=utf-8

Those are very tiny ones, they may be fruit fly larvae. Good thing you took that out when you did. It only takes about 48 hours for them to breed and multiply. One tip if you get fruit flies: If you have a kitchen bucket with a snap lid, leave it cracked open for a few hours or overnight. Without touching it or moving it first, rapidly slam it shut and seal it. Then take it out to the compost. Fruit flies fly up rapidly if they detect movement so you want to get them all in there and slam the lid on.