Q.Does my tomato plant have blight
It is dying and I’m at a loss for what to do. The plants appeared to be okay when I bought them, but now they have brown blotches on the stems. The stems are turning brown, hard and then dying, but the tomatoes are still slowly growing. I purchased them at my local Home Depot already potted and growing fruit. ? Please help.
Yes, this appears to be late blight. Likely the plant was stressed from a long time in the greenhouse and pot.
Here is an excellent article with some treatment options.