How to Identify Tomatoes With Yellow Leaves
- 1). Examine the leaves for signs for yellowing and curling at the edges. This is a sign of the tomato leaf curl virus. This virus will not prevent the plant from growing edible fruit, but fewer fruits will be produced.
- 2). Check the leaves for yellow, brown and black sections that look like they are rotten. Yellow leaves may also fall off the plant and be on the ground, symptoms of early blight. You'll need to remove the plant by the roots before the disease spreads to nearby plants.
- 3). Examine the leaves for signs of yellowing, bushiness and stunted growth. Cucumber mosaic virus prevents the tomato plant from growing properly, leaving it with small, mottled, yellow leaves. Tomato plants with this virus must be removed from the ground and thrown out in a yard waste bag.
Source...