Quick Answer: Verticillium Wilt of Tomato Plant
Verticillium wilt is a soil-born fungus. It can survive for 4-5 years in unfavorable and up to 15 years under favorable conditions. An infected leaf of verticillium wilt of the tomato plant turn yellow, wilted, and looks burnt. Fungicides could be used as prevention but they are not reliable for the complete cure of the disease.
This is a comprehensive guide on verticillium wilt disease of tomato plants, including why/how it infects, symptoms, prevention, and management tips.
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- Quick Answer: Verticillium Wilt of Tomato Plant
- What is Tomato Verticillium Wilt Disease?
- How Verticillium Wilt Harm Tomato Plants?
- How to Confirm that Verticillium Wilt is Troubling your Tomato Plants?
- Ways to Control Verticillium Wilt Disease on Tomato Plant
- How to Prevent Verticillium Wilt on Tomato Plant
What is Tomato Verticillium Wilt Disease?
Verticillium wilt of tomato plant is a soil-borne fungal disease. The fungi that cause verticillium wilt in the tomato plant are Verticillium dahliae and Verticillium albo-atrum.
The sexual spores of Verticillium are conidiophores. Verticillium overwinters as tiny black resting bodies called microsclerotia.
It affects the xylem vessels in the spring season. It releases certain toxins and spores that infect the vascular tissue and clogs the pathway of nutrient transfer, making plants nutrient deficient.
Brown streaks under the epidermal layer caused due to xylem clog and fungal toxins are an important identification mark for verticillium wilt.
How Verticillium Wilt Harm Tomato Plants?
Verticillium species attack the tomato plant at any stage of their development, including when they produce fruit.
Verticillium from its resting spores [Microsclerotia] under cold conditions [50-54°F (10-12°C)] can survive for up to 8 years in the soil. Soil temperature of 75°F (24°C) is optimum for infection, with 55°F (13°C) minimum and 86°F (30°C) maximum.
The fungus survives in plant debris for up to 80-90cm. Verticillium survival is ensured by mycelial fragments in plant debris and by microsclerotia.
It can survive as a pathogen on different hosts. It colonizes the root and lives in the soil for as long as 10+ years.
How Verticillium Enters The Plant System?
The fungus enters the plant through roots. It can either find its pathway to the root directly or enter through root injuries. These root injuries can happen due to-
- Root-Knot nematode.
- Use of cultivar.
Verticillium fungus enters the roots through its mycelium and germinates microsclerotia at the temperature of 10 and 20°C.
The fungus initially spreads its infection xylem tissue of the tomato plant. It gradually colonizes the xylem. The infection reaches to lower leaves and clogs the water and minerals passage.
This results in the death of the leaf due to nutrient deficiency.
Soil with microsclerotia is easily dispersed by air currents, as well as water splashes and soil insects. The contamination can occur through infected plant debris.
Check out this video for Verticillium Wilt of the tomato Plant –
How to Confirm that Verticillium Wilt is Troubling your Tomato Plants?
As verticillium wilt affects the vascular tissues [Xylem and Phloem] of the tomato plant, symptoms occur on one side of the plant.
Symptoms as they usually occur
Early Symptoms of Verticillium wilt of the tomato plant –
- Wilting of lower leaflets.
- Yellow spots appear on the lower leaves of the plant.
- The initial wilting of the leaves is reversible, that is, in the afternoon, when they are actively transpiring, leaves do not show signs of wilting but later at night, lower leaflets wilt.
- Leaves die and fall off on the ground.
As the disease develops,
- Intervenous sections of leaf, V-shaped sectors of the leaf of leaflets show irregular yellow appearance due to toxins produced by fungi.
- V-shaped sectors of leaves lose turgidity due to water deficiency.
- The lower part of the stem or branch that is at the bottom of the soil line shows brown-colored streaks on its insides.
- A considerable part of leaflets shows a beige-brown appearance.
- Leaves become necrotic.
- Affected leaves and stems die prematurely.
- Stunting of the tomato plant.
- Fruits are small and show yellow sides.
- Plant may Die
The diagnosis of the verticillium wilt of the tomato plant required vertical cutting of a bottom fresh stem of the plant.
A discoloration or brown marking will be seen on the inside of the stem where vascular tissues are predominant.
Look for the stems 10-12 inches above the soil, the symptoms might not be present there because the verticillium wilt of the tomato plant does not affect the upper leaves and stems. These stems, when cut in half, will be green from the inside.
A laboratory test for the verticillium wilt should confirm the disease.
Ways to Control Verticillium Wilt Disease on Tomato Plant
There is no way you can control the disease once it has started to spread, but there are ways by which you can manage the symptoms and can save your healthy tomato plants.
They are known to be of little help overall but may help in delaying overall impact.
It is always recommended to spray the fungicide during the evening. During the afternoon, there is a chance that leaves could get burnt because of chemicals present in the fungicide.
One should always look for the following instructions before applying fungicide-
- Directions of use
- Quantity dose.
- Environmental conditions under which fungicide works effectively.
Fungicide solution of thiophanate-methyl and benzimidazole is effective against verticillium wilt disease of the tomato plant.
Spray fungicide to the base of the plants.
How to Prevent Verticillium Wilt on Tomato Plant
Prevention is the best way forward against Verticillium wilt.
Here are some of the ways –
Plant Resistant cultivars
Using varieties resistant to Verticillium wilt is the most practical solution to the disease.
These seeds might not produce tomatoes with good yield but will lower the risk of fungi disease.
Resistant seeds are designated with the letter ‘V’ for verticillium. ‘VFN’ signifies resistance against root-knot nematodes.
Provide Optimal Nutrients to Plants
Verticillium wilt seems to strike “root stressed” tomato plants more than the healthy ones.
One way to reduce plant stress is to provide your plants with optimal nutrition.
Avoid Infection from Soil, Plants & Tools
If you had verticillium wilt in your garden, make sure you do not plant (if the species is not resistant) in the same soil.
Another way the disease spreads is with infected tools, ensure the tools used for infected plants are sanitized properly before using them at other places.
Remove plant leaves, roots, and dead parts of the infected plants.
No, the tomato plant cannot recover from verticillium wilt, but using some preventions and control ways can help you in managing the plants with the disease.
Some tomato varieties resistant to verticillium wilt are- Jet Star VF1, Big Beef VF1F2NTA, Beefy Boy VF1F2T, Florida 91 VF1F2, Crista VF1F2F3N, RTF 6153 VF1F2 and BHN 602 VF3.
The number written indicates the race of the fungus.
Remove all the infected plant debris.
Fusarium wilt affects the whole tomato plant, whereas verticillium rarely infects leaves and stems that are above 10-12 inches from the soil.
I hope this guide provided valuable insights into the disease, it’s spread, and how you can prevent it.
If you have come across verticillium wilt in your tomato garden, what methods did you implement? Do share!
Feel free to share this with your friends and family who love gardening.