tomatoes plant wilted is this a bacteria or fungus?
We have planted some heirloom plants for the first time this year.I pulled out a Brandywine because I thought it might be infected with something that would spread to the others. It was not thriving well anyway. I noticed two days ago it's neighbor plant (Prudens Purple) was wilting badly and had aphids. I sprayed it with insecticidal soap which seemed to help a little yesterday but today it looks very badly wilted and I noticed on further inspection that it has a brown patch girdling the base of the plant at the soil line. Can anyone tell me what this might be? Two other things I should add. This year I added compost from the pile in the fall which I worked into the soil in early spring. Also I have been planting tomatoes in this same spot for several years with a break about four years ago when I let the whole garden lie fallow. I also ammended the soil with dried blood for nitrogen and potash for potassium since my soil test showed my ph was fine and my phosphorus was fine. The plants all around this one seem to be fine so far though I am nervous about them. I sprayed all with the soap as a prevention against the aphids. Is this a fungus or a bacterial wilt? I have very little experience with plant diseases and would appreciate sokme expertise here!