How to Fix It
What it looks like:
Yellow blotches appear on the lower leaves. As the blotches spread, the veins in the leaves turn brown. After the leaves turn brown, they fall off. The disease progresses up the stem until the plant is stunted.
What causes it:
A fungus that lives in the soil, Verticilliurn albo-atrum, attacks the roots and travels up the xylem tubes with water. It then prevents the normal flow of water and nutrients to the leaves.
What to do about it:
Once plants are infected, there isn’t much you can do to treat Verticillium wilt. Rotate your crops, because the fungus can live for long periods in the soil and even live among weeds such as ragweed. Choosing wilt-resistant varieties to plant is the best way to prevent Verticillium wilt.