Larvae on tomato shoots
I have some small tomato shoots in pots (the leaves are just starting to appear now) and they've been spending most of their time outdoors lately because it's been warm. Yesterday I noticed tiny white larvae crawling around the soil in one of the pots, around the base of the shoot. I presume a moth or other flying insect laid them there, and I can't see any in the other pots yet.
Does anyone know what they might be, and whether they're a threat to the plant?
Here's a couple of photos with a paper clip to indicate scale. And one of the tomato plant. I have no greenhouse but there's been plenty of sun over the last month, so I was expecting them to have grown more by now: