The damage looks like cabbage root maggots to me, but then you should see tiny white maggots in the soil near the roots and on the root itself. Also, they do not like the heat and more a problem on the north, then on the south.

Yeah did you dig around in the soil to see what was there? If you dig the plant up rather than pull it you can learn more.

Most likely it is the heat. Brocoli is a cool weather plant, often planted in the fall to be harvested in the late spring. I tried an experiment this year by planting my leaf brocoli under lights in January and transplating it into a raised bed in early April. So far, so goo, but I am not holding my breath as the weather gets warmer.

is there any way to get rid of them and salvage my plants?

Once planted there isn't much you can do to treat for CRM that I know of that wouldn't also kill the plants - before planting, yes - beneficial nematodes, soil sifting, soil solarization, pesticides mixed into the soil, heavy spring tilling, etc.

If you still have live plants leave them, mound up soil around the bases, and some will likely make it as more of the larvae pupate and hatch to leave.

Dave

Lightly fertilizing, hilling soil around the plants up to the first healthy leaf, and watering well for a bit may help, they may perk up by growing new roots from the stem. Keep the plants healthy from the get go and hill them and you won't have a problem in the future.

Root maggots are a major issue around here. I posted a thread a couple weeks ago about using row covers to stop the adult flies from laying eggs in the first place, if you want to do a search for it. There's also a thread on using tulle as a barrier against other small insects.

I finally decided to splurge on something called Proteknet Insect Netting which comes by the roll and is cheaper than tulle when purchased in bulk.

a little secret, at planting time ad some powered ginger in the planting hole and on the surface near and even on the plant. sprinkle some every week or two. till plants are larger.hope this helps. works for all in the cabbage family.