I had a couple month old tomato plant (unknown heirloom yellow cherry variety). I grew it from seed that I kept from plants I received last year. It had a healthy life, but around 2 weeks after transplanting it outside in the yard (late May), portions of it started to wilt. Only certain branches, or side of a branch. I treated it normally for around a week to see if it persisted, but it only got worse. I removed it for fear that it was a disease that might spread to my other 5 plants (which do not have these symptoms) I did a bit of an autopsy to look for clues. New roots had grown where I buried the stem. I read that bacterial wilt can be identified by discoloration or milky ooze in a cross section of the stem, but I observed no sign of this. No knotting of the roots, or ants present either. I would hate for this to happen to my other plants. What killed this plant and how can I prevent it?