Scabs on Stems of Tomato Plants
live in the Great Lakes region and am pretty sure that some of my tomato plants have pith necrosis. I first thought they were cankers but with a little more research, seems to look more like pith. Nothing wrong with the leaf, it is all on the stem and looks like scabs! What can you tell me about it and what is the treatment, I have read about two different treatments...one is the plant will outgrow it and the other is to remove the plant or it will spread.
I think I have good news for you. If your plants look healthy other than the “scabs” on the stem I do not think you have pith necrosis. That disease is more of a problem in warm climates. I could only find reports of this disease in greenhouse labs. The symptoms include black streaking on the stem, chambered pith (inside the stem) and wilting. The scabs on your tomatoes’ stems are probably normal swellings that have the potential to form adventitious roots. If the plants look normal other than the scabs I would not worry. Plus as you discovered the plants usually outgrow the disease. Check out the Alabama A&M and Auburn Universities publication Wilt Diseases of Tomatoes. It has some good pictures and great descriptions of common tomato wilt diseases.