Hello All. I am new to the forum and new to growing tomatoes. Everything has been going pretty well, but I am starting to see evidence of at least one pest/disease. I haven't been able to identify exactly what kind of problems I have from web searches alone, so I thought I'd throw it out there for the more experienced to take a crack at. I live in San Diego near the ocean, so my climate is quite mild.

I have several plants with varying problems, so I'll post each problem as a separate conversation. Here is the first:

Early Girl 50, about 2 months old. One tomato ripened already, though I think it was unusually early. Several others are still quite green. I have trimmed the leaves away from the ground by about a foot. It is in a pot, and I water it deeply 2 or three times a week. Some leaves have started to turn yellow and now some dark spots are appearing. I haven't seen any insects or eggs on the plant. I have attached a picture.

Any ideas what it is and if I should be concerned?

Thanks!