Brassica Update

Getting brassicas established is always a worry for me. Their roots seem to be very prone to insect attack in their early days. I use brassica collars and nematodes to protect them, but I always keep some spare plants for as long as possible in case I need to replace any casualties.
This Brussels Sprout looks healthy enough, doesn't it?

It is one of those that was nearly submerged by rampant Parsley until a few days ago when the Parsley got cut back:

This year I am only growing one plant of each of four varieties of Brussels Sprout, so I am particularly vulnerable. In this bed there are four Brussels Sprouts down the centre, and eight "De Ciccio" Broccoli plants along the sides - and of course the Parsley, which extends for about half the length of the bed.

The Broccoli is just starting to form its heads. This crop will mature much sooner than the Brussels Sprouts, which won't be ready until late Autumn / early Winter.

One of the Broccoli plants is obviously affected by a root fly of some sort. The leaves are wilting, and they are dull and lifeless. It may pull through if I keep it well supplied with water, but it's doubtful.

These are the nematodes I use. Recently I have bought them from a firm called Green Gardener, who seem very efficient and reasonably priced. The nematodes are not 100% effective, but they do reduce the problems a lot.

Let's hope it is only the one plant affected, because I don't have any spare Broccoli plants. However, I do have lots of spare Brussels Sprouts.

Actually, this Broccoli plant looks as if it's two, so maybe I do have a spare! (Looking closely I found that this is one plant with two stems, not two plants.)

What do you think I should do? Snip off the weaker stem, maybe? Or just leave it?
Elsewhere, I have some PSB and Cabbage seedlings coming on. Some of them are still too small to be transplanted, like the ones in the foreground of this next photo:

But these aren't. They are "Mila" Cabbages, a Savoy type. I reckon Brassicas are OK to transplant into individual pots once they have produced two proper leaves, not counting the cotyledons or "seed-leaves".

These are "Rudolph" PSB:

When potting-on these seedlings, I selected the strongest ones, but I also kept a few of the others, retaining them in their original "seed-bed" pots. If I don't need them, I will give them away or compost them.