tomato plant

Question

What are black spots (do not have yellow rings around them) on tomato leaves? Black spots appear along veins in leaf.

Answer 1

If the spots are distinctly only on the oldest leaves, your plant may be suffering from Septoria Leaf Canker, but there are numerous other possibilities. These articles may help you identify the issue and treat it appropriately:

https://www.gardeningknowhow.com/edible/vegetables/tomato/septoria-leaf-spot.htm

https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-plant-problems.htm