Hi Carolyn

Thanks so much for reaching out.
And thank you for the photos as they've helped in the identification of what appears to be Root Aphids (Pemphigus). If it has 6 legs, it's a Root Aphid.

Root aphids can overwinter as eggs and may feed on plants such as sedum, veronica, aster and coreopsis, oregano, basil, and hosta. Root aphids have piercing-sucking mouthparts; however, they feed on root tissue as opposed to plant leaves.

Damage:There is usually visible lack of vigor from plants that are damaged from root aphids. Note the withered, curled and yellow leaves - similar to signs of nutrient deficiencies. Fruit and blossoms on aphid infested plants will be small, stunted, and generally less desirable as nutrition is siphoned away from them.

Root aphids can leave plants vulnerable to root rot, mildew, and disease.

Root aphids may also be accompanied by ants.

Control:
Remove and destroy all infested plants.

One of the best methods to avoid root aphids is through prevention. General garden routines, such as weed control and even watering, can greatly reduce the likelihood that root aphids will invade. Turning and working the soil in the fall will also help to prevent the overwintering of this pest. Tilling the soil prior to planting in the spring and rotate susceptible crops will also help keep them away.

Root aphids are not what I would refer to as a spreading pest in the garden. However they may be transported from one container to another via transplants or rooted cuttings.

Don't forget to remove all weeds and keep the garden free of debris.

University of Idaho Extension, Root Aphid:
https://www.uidaho.edu/extension/ipm/pests/aphid-adelgid/root-aphid

University of CA, Root Aphids:
http://ipm.ucanr.edu/PMG/r102300711.html

I do hope this information is helpful.