You might want to try this stuff.....
Nature’s Good Guys
https://www.naturesgoodguys.com/
Beneficial Nematodes
https://www.naturesgoodguys.com/collections/beneficial-nematodes
There’s also this place, Arbico Organics, but it seems like Nature’s Good Guys is cheaper.
Arbico Organics
https://www.arbico-organics.com/category/beneficial-nematodes
Arbico Organics has some good stuff. I’ve been using their braconid wasp larvae for fly control since we built this place.
I’m sure they’ve got other things that would be of benefit here. I just need to take some time to peruse the offerings.