Ground pearls belong to a family of scale insects. Ground pearls are identified by the presence of small pearl-like bodies on the roots or in the soil. The pink adult stage that crawls is present during early summer. The adult female ground pearl is a wingless, pinkish scale insect, about 1/16 inch long with well-developed forelegs and claws. The male is a gnat-like insect smaller than the female, but with a slender waxy "tail" up to 1/4 inch long. Clusters of pinkish-white eggs are laid in a white waxy sac. Commonly referred to as a ground pearl, the slender nymph is covered with a hard, globular, yellowish-purple shell. Encysted nymphs are up to 1/16 inch in diameter
You are right, there is not a lot of info on that beast or how to control them. It seems they are scale and it seems to me that I control it with insecticidal soaps. But that is normally as a foliar, I am not sure how much good it would do as a drench. They are obviously opportunistic so there is something going on in the soil that allows them to flourish.
Try an insecticidal soap, WTF
I think I would have to blast them with some quality AACT and see if you can get something to compete with them and knock their numbers back. They seem to have free reign
They must have a natural predator, I just haven't found it yet.