Only on dandelions.

When I thought I heard of them all a new one pops up, or below. Had to look it up and appears to be a hard pest to control, good luck.

Yes, never heard of them and hard to control. I'm just beside myself. In this small new garden I have more pests than I had in over 60 years of gardening in 3 states and various places within those states. At 81 I just didn't need this--lessening energy, limited income and garden now demanding more energy and expensive products.

But I can't not garden; I wouldn't know how to feed myself without my vegetable garden.

Porkchop, you've seen root aphids on dandelions?

Yes, the AI that came up suggested insecticidal soap so I drenched with Safer Insecticidal soap, then phoned Safer. Safer Insecticidal soap is not effective against root aphids I was told. As for Beauveria bassiana this is on the Arbico website:

Naturally occurring in the soils of numerous regions globally, Beauveria bassiana is mainly used to target foliar pests as many soil dwelling pests have developed a natural resistance to B. bassiana since it is native to such a range of regions. For this reason, close examination of the pest insect(s) for correct identification should be done before applications to the soil are made.

With AI so uninformed, I'm not likely to use hydrogen peroxide. Here's one informed opinion:

Jeff Gillman, Ph.D., author of The Truth About Garden Remedies and director of the UNC Charlotte Botanical Gardens notes, “In my limited tests and experience, it [hydrogen peroxide] is absolutely useless for controlling disease.” Of course, root aphids are not a disease, but neither does drenching the soil with the product seem likely to be effective.

It's not going to be an easy or cheap fix and I expect I'll be dealing with it for some seasons, though I hope not the rest of my life, short though that may be. I'll be 82 next season.

"Porkchop, you've seen root aphids on dandelions?"

Yes. Not on all dandelions I pull, but quite often in a certain section of the property. It was quite shocking the first time I pulled up a root and saw them LOL!

They haven't spread to ornamentals or vegetable garden?

Note too that AI's recommendation for insecticidal soap was also wrong.

"They haven't spread to ornamentals or vegetable garden?"

I see them most on the dandelions in the vegetable garden, but I've not noticed them on other plants.

Sounds like you've been very lucky. I was told they will move around the garden.