something is wrong with my basil

[Spice Princess]

I had bought 2 Genovese basil plants and put them in a large container about a month ago. When I bought the plants, they had a few yellow leaves, but I didn't think anything of it because they were on the bottom row of plants and I thought they probably weren't getting enough sunlight.
About a week ago I went out to check my plants early in the morning and noticed that many of the leaves on both basil plants had blackish-purple streaks on them and were looking a little dry around the edges. Some of the lower leaves were also very yellow and fell off easily when I touched them. When I inspected the plants, I found a few tiny brown worms on the leaves. I killed the worms, but I found more the next day. I killed those too and sprayed the plants with a mild dishwater solution, which my Mom says acts as an insecticide. I haven't found any more worms, but the plants don't seem to be recovering -- they aren't putting on any new leaves, and it looks like even more of the leaves are turning black. I had pulled off all the leaves that looked too badly damaged, but I'm afraid to pull off any more because they will hardly have any left.
Help! Does anyone know what this might be? I am completely stumped, and at this point I'm not even sure if the black leaves are caused by the worms or perhaps some disease.

[adopt a greyhound]

This may help.

http://www.gardeningknowhow.com/herb/basil-diseases.htm

[Spice Princess]

Thanks for the link! I don't think that was the problem, but it's good to know that for future reference.

I actually called the local plant store and they said it was probably a different type of fungal infection. They recommended a copper solution fungicide (suitable for organic gardening), which I applied and the plants are already looking much healthier. I pulled off the dead leaves before treating the plants, and they are already putting on new leaves which seem uninfected so far.