I have exactly the same problem. Seedlings getting nibbled at. so the other night I went out with a flashlight and there were little black bugs all over my young spinach, radishes and lettuce. Baby earwigs, maybe? There were hundreds of them(maybe thousands). I dumped a lot of diatomatious earth around the plants which seems to slow them down but not entirely. Then it rains and gets washed away. Very discouraged- reading all the comments and no one has the answer for what these bugs are and how to effectively get rid of them! These are not ants- they look more like a short black pin or piece of lead pencil.

It's a type of Maranta.It isn't dead yet,just severly stunted.Cut away all the inflicted portions and feed it well in March.It'll grow back but very slowly.If you water it with distilled or purified water it'll be ok.

I've read about ants making nests in the roots of a tomato plant, with the result being a dead plant. I think the problem is that they remove enough soil that the roots dry out. Here are some home remedies which shouldn't affect the tomatoes: = Sprinkle diatomaceous earth (DE) in a ring around the nest. When ants walk through this, it pierces their exoskeletons and they will die. [DE is a rough white powder, the fossilized skeletons of diatoms, a type of algae. It is sold in some garden centers. You could also try agricultural supply places or stores that feature organic foods and other natural products.] = Mix 1 cake of yeast with 1/3 cup of sugar and 1/3 cup of molasses. Put it in low lids near the ant nest. Ants love sweets and will take it back to the nest; the yeast will expand inside their bodies and kill them. [Freeze whatever you don't use.] = Crush grains of white rice with a mortar and pestle. Sprinkle it around the anthill. The ants will take it inside the nest. It will expand inside their bodies and kill them. (Some people use grits instead of rice. Powdered tapioca should work too.) = Mix 1 part sugar with 2 parts borax. Add enough water to make a gel. Put this bait on squares of cardboard or low plastic or metal lids (low enough that ants can enter and leave easily; you can also raise the dirt around the sides of the lid to make a ramp). The ants will take this back to the nest and they will all die. [Too much borax isn't good for tomatoes, so don't use a lot of this in the garden.]

Sorry for the delay in responding. I'm having trouble uploading the pictures I took. I established my account on my IPad but it doesn't take good close up pictures, so I took them with my camera and I cannot seem to get the system to recognize them. Anyway, unless someone can tell me how to upload via my computer with an account established on an IPad, I will have to wing this without them. The leaves get brown spots, then curl and dry until the entire leaf stem dies back to the main stem. This is the second year this has happened and all of my tomato plants, even ones I planted recently, are reacting the same way. I need to figure this out. I cut the stem and there is not any brown inside. It looks fine. We rotate our crops as much as possible for a relatively small garden (20'x20'). We are not planting in the same area one year after another. The brown spots and die back begins within a few weeks of planting. We have had very dry weather conditions but we have a soaker hose system, so we have kept things generally well water except when we went on vacation. It dies back from the bottom up. The bottom of the plant is leafless, while the top continues to grow and produce tomatoes. The entire stem dies, flower buds and all. I may try to sign my husband up from the computer to see if I can upload the pictures.