Depends on what it has. Did this happen really quickly? (like in a day or two) If it turned brown quickly and has Late Blight, bad news. Has to be pulled out, bagged up and sent away. If it has early blight it can be controlled with Daconil Fungicide. My tomatoes have some early blight and as you all know I have been getting tomatoes like crazy. I just spray weekly with the Daconil. If it has any of the wilts (Fusarium or Verticulum) Those are in the soil and there is nothing you can do for this plant. Pull it and again bag it. No composting of deseased plants. Amend the soil with PLENTY of compost. Plenty! Add Seaweed fertilizer, add lime and add Crab Shell (sold as a fertilizer). You can buy Seaweed Fertilizer and Crab Shell from Neptunes Harvest.
http://www.neptunesharvest.com...
