Last year something ate many of my beets. The beets looked beautiful until you pulled one and half of the beet was gone. I could find no trace of any pests and am at loss as to what is doing the damage. I lost half my row to these pests. Do slugs eat beets?
Something Eating My Beets
Certified GKH Gardening Expert
It sounds like what you have is a root maggot problem. There are many species of root maggots so their color may vary from one to another. However, their taste for root crops, like beets and radishes, is the same. Here is an article that you may find helpful: https://www.gardeningknowhow.com/plant-problems/pests/root-eating-insects-identifying-vegetable-root-maggots-and-root-maggot-control.htm