Verticillium Wilt

An Intro to Verticillium Wilt

Verticillium Wilt is a fungal disease affecting the vascular system of host plants. It is caused by three species of the Verticillium genus. Tomatoes, potatoes, eggplants, and peppers are most vulnerable. The disease obstructs the flow of nutrients through the xylem, resulting in wilting of the leaves and stem and eventually the death of the plant. Symptoms look very similar to Fusarium Wilt, but verticillium can kill small plants very quickly. Tissue discoloration will be evident if the stem of an infected plant is cut.

CONDITIONS

Verticillium is even hardier than Fusarium and thrives at cooler temperatures. It can survive very cold--even freezing--conditions.

TRANSMISSION

The fungus is transmitted through contact with infected soil or water and through root-to-root contact. Some types of insects can also spread the disease from plant to plant.

MANAGEMENT

Like Fusarium Wilt, there is no practical cure for an infected plant. The fungus continues to live in the soil after a plant is dead and can infect any new plants it makes contact with. Farmers often use crop-rotation as a strategy for minimizing the spread of verticillium. Verticillium does not tolerate long periods of flooding, and continued drowning of soil over a long period of time might be one way of ridding it of the fungus.

AVOIDING VERTICILLIUM

The best way to avoid verticillium is to plant cultivars that have been bred to resist it. CLICK HERE for a complete list of Verticillium-Resistant Tomato Cultivars.

NOTABLE VERTICILLIUM SPECIES

V. dahliae, V. albo-atrum, and V. longisporum are the three well-known species.

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Fusarium Wilt

An Intro to Fusarium Wilt

Fusarium Wilt is a fungal disease affecting the vascular system of host plants. It is caused by the Fusarium oxysporum fungus. Tomatoes, beans, sweet potatoes and bananas are particularly susceptible. The disease causes wilting and eventually death of the plants leaves, starting near the bottom and moving up. The plant becomes stunted, the leaves yellow and fall off, and eventually the entire plant may die.

CONDITIONS

Fusarium oxysporum can survive most climates, but is particularly active in warm, moist conditions.

TRANSMISSION

The fungus is transmitted to the plant through contact with soil and can spread to other plants on gardening tools and fingers and by splashing water. The disease starts at the roots and moves up through the plant.

MANAGEMENT

On a small gardener's scale, there are few practical solutions to the problem of a Fusarium infection. The fungus can live in soil for a long time and that soil should not be used again. There are fungicides that can eradicate the disease from the soil, but they may be difficult or impossible to acquire in a small place like Pohnpei. Diseased plants can infect nearby plants, spreading the fungus throughout your garden. Affected plants will have decreased fruit yield if they survive at all.

AVOIDING FUSARIUM

It may not be completely avoidable, but you can minimize the risk by planting in quick-draining soils, keeping plants out of the elements, and not over-watering. Even better, use plant cultivars that have been bred to be resistant to the pathogen. CLICK HERE for a complete list of Fusarium-Resistant Tomato Cultivars.

NOTABLE FUSARIUM SUB-SPECIES

F. oxysporum lycopersici is the sub-species that affects tomato plants.

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