Diseased Tomatoes EVERY YEAR!!

For 3 years, maybe 4?, I've had a problem with my tomato plants. For sure, they have a disease, but I don't know which one.

I described my problem via email to U of I's agricultural ext., but I think they misdiagnosed my problem: bacterial spot/speck. I don't think it's this because after viewing images on-line, I don't have raised bumps/specks on my tomatoes.

My symptoms are a brownish spot/marking on lower leaves that eventually yellows the leaf and stem, which makes it easy to break off at the main stalk.

Eventually the disease on the leaf spreads to other leaves, and moves higher up the plant, etc. May appear as a spot or brown marking on the stem as well. I do get fruit, but nothing like the yields I had in the 3 previous years. They're smaller too.

I do rotate the crops yearly, pull out all dead material in the fall. In spring, I add peat moss, and mushroom compost and roto-til the soil and rake even.

I start my tomatoes from seed at home with clean containers. Problem doesn't present until plants are growing in the garden.

I do fertilize with miracle-gro tomato fertilizer, as well as vegetable miracle-gro for the other vegetables.

I don't have any pictures to send otherwise I would.

Please help if you can....I am so over this problem and putting in all the hard (yet fun) work that goes with gardening, to have such a small yield (and fruit size)....it's frustrating.

Thanks much,

Natalie