Tomato Diseases: How to Identify and Treat Verticillium Wilt

The fungus works its way up through the plant’s roots, clogging water-conducting tissue in the stem. It spreads a toxin that wilts and spots leaves and prevents water from reaching branches and leaves, starving the plant. Infected plants usually survive the season but are stunted. If they produce any fruit, it’s small and underdeveloped.

What does verticillium wilt look like?

Photo: University of Massachusetts Amherst

• Yellow spots appear on lower leaves, followed by brown veins. Leaves then turn brown and fall off. Infection pattern often resembles a V-shape. Symptoms progress up the stem.
• Plants may wilt during the day and recover at night.
• Interior of main stem (when split) shows discolored streaks about 10-12 inches above the soil line, the result of plugged water-conducting tissue.
• If cool conditions persist, the plant may die.

When does verticillium wilt affect plants?

• The fungus thrives in cool temperatures and when soil is moist and not too warm (60-75ºF).
• It can attack at any stage in a tomato plant’s growth, but is most common when plant is producing fruit.
• Plants in poorly drained soil are more susceptible to infection than those in well-drained soil. Wet soil allows the fungus to multiply and move up through the tomato plant’s water-conducting tissue.

How do verticillium wilt symptoms differ from symptoms of other diseases?

How do you control and treat it?

• To date, there is no chemical treatment available.
• To slow the disease, use fertilizers lower in nitrogen and higher in potassium.
• Destroy infected plants.

How do you prevent the fungus?

• Rotate crops. The verticillium fungus can survive indefinitely in the soil. Plant tomatoes no more than once every four years in the same spot. Avoid planting other Solanaceous crops (potato, pepper, and eggplant) in the same area, too – they are susceptible to the fungus.
• A “V” listed after the variety name on its label indicates its resistance to the verticillium fungus.
• Plant tomatoes in well-drained soil.
• Remove and destroy affected plants at the end of the season.

Extra facts to know

Return from Tomato Problems: Verticillium Wilt to Tomato Dirt home

New! Comments