Verticillium wilt is not fun, and if you have it, you know how devastating it can be. It’s a serious disease that can quickly turn your gardening season on its head.
Sometimes called “vert,” it’s a soil-borne disease that attacks hundreds of different plants. There’s no cure, and it can turn a once-happy crop into a mass of wilted leaves in no time flat.
Now that we got the bad news out of the way, don’t lose hope. There’s plenty you can do to tackle this terrible foe.
What is Verticulum Wilt?
Verticulum wilt is a disease caused by a fungus in the soil. Plants pick up the disease via their root system, where the infection quickly spreads from root to tip.
The fungal infection is a death sentence for affected plants. As it spreads, it effectively cuts off the water supply to the plant’s foliage by causing the cells in the stems and branches to plug themselves.
According to the Morton Arboretum, there is evidence that there are two types of verticillium wilt that kill plants at different speeds: “There seem to be two forms of the disease, one in which plants die slowly over several years and another where they die rapidly within a few weeks.”
How Does Verticulum Wilt Spread?
Within a plant, the disease spreads through the vascular system. Garden wide, it spreads through the soil, where it can live indefinitely.
Signs of Verticillium Wilt
Verticulum wilt looks a lot like other plant diseases, so it’s challenging to spot, especially in its initial stages. Signs and symptoms of the disease include:
- Yellowing and curling of leaves
- Leaves may turn brown and the plant loses foliage
- Portions of plants, like entire stems and branches, may die back
- Dark-colored patches on plant material
- Trees may display signs of cankers or diseased, dead bark
- Stunted growth
Signs vary depending on the type of plant and species, so it’s difficult to pinpoint an exact set of symptoms to look out for.
In some plants, like spinach and cauliflower, signs of infection don’t appear until after flowering. In other plants, discoloration shows up on a single side of the plant or affected leaves.
With woody plants, symptoms aren’t necessarily acute in nature and may occur only in isolated portions of the plant. In infected trees and shrubs, the disease may display a different symptom pattern than in edible plants like tomatoes, recurring intermittently and not necessarily from year to year.
Chronic infections in woody plants are also possible and show up visually in tree rings. A chronic infection doesn’t necessarily mean a quick death for a tree or shrub and infected plants may just show signs of slow growth. Plants may display both types of symptoms.
Signs of the disease don’t always show up right away, either. Often, you’ll notice the symptoms only once the summer heat has kicked into full swing.
Other Diseases Can Look Like Vert
The discoloration of plants isn’t necessarily a sign of the presence of the fungal disease itself. It’s sometimes a symptom of the infection. Discoloration and yellowing can also be a sign of poor environmental conditions, making it even tougher to spot verticillium wilt.
There are plenty of diseases that have similar symptoms (including fusarium wilt, another type of fungal infection) so it’s difficult to determine the cause of symptoms with just a quick inspection of foliage.
How to Know If You Have It
So how do you figure out if the disease has found its way into your garden soil? Testing is the most accurate way to diagnose the problem.
If you’re concerned about the potential presence of verticillium wilt in your soil, consider testing your soil prior to planting trees, shrubs, and perennials.
Which Plants Are Vulnerable to Verticillium Wilt?
The list is, unfortunately, extremely long. The disease affects trees, ornamentals, and edibles. It’s also a common affliction of tomato plants.
Certain plants are more vulnerable than others to the disease. When shopping for plants or seeds, choose disease-resistant varieties that aren’t as susceptible to verticillium wilt.
Young, tender seedlings are more susceptible to this disease than mature plants. Mature plants, even when infected, may be able to live with the disease if cared for properly. Plants that are already unhealthy to begin with are also more likely to die when infected with verticillium wilt.
In a vegetable garden, you’re most likely to spot the disease on tomatoes, strawberries, and cucumbers.
It can also affect a variety of weeds such as dandelions, pig’s weed, and sagebrush. Controlling these susceptible weeds prevents the further spread of the disease.
Here’s a list of common garden plants that may be affected by the fungal disease (note that this list is not exhaustive):
- Maple trees
- Ash trees
- Catalpa trees
- Smoke trees
- Cherry trees
- Magnolia trees
- Walnut trees
- Elm trees
How to Prevent Verticillium Wilt
The key is to care for plants so that they’re able to ward off the disease. Your first step should be to plant and buy plants that are resistant to the fungus.
Don’t plant susceptible plants in areas where you’ve spotted verticillium wilt. Avoid overfertilization (particularly with nitrogen) to help prevent the disease from popping up in your garden.
Sterilize gardening tools to avoid the spread of verticillium wilt. Get rid of dead and diseased plant material in your garden. Prune diseased or dead branches. Don’t forget to clean off equipment, like pruning shears, after getting rid of infected branches and such.
Other strategies for preventing verticillium wilt are commonly used to avoid other soil-borne diseases: crop rotation and maintaining a healthy garden environment.
Keeping your garden plants watered without flooding the soil is one of the recommendations for reducing instances of the disease.
How can you prevent verticillium from making its way into your garden soil? It’s rather tough to do. There are many ways to infect soil including buying contaminated products from nurseries and buying potting or soil mixes that have not been properly sterilized.
Even the most diligent gardener might find themselves having to deal with this formidable fungal opponent. But by taking care to clean tools, rotate crops, and cultivate healthy soil, you’re less likely to encounter problems with this fungal disease.
Which plants are less susceptible to verticillium wilt? Check seed information to find out whether a plant is resistant to this particular disease. Also, here’s a non-exhaustive list of disease-resistant plants less likely to fall victim to this fungal infection:
- Birch trees
- Some cultivars and species of oak trees
- Dogwood trees
- Poplar trees
- Willow trees
- Mulberry trees
- Baby’s breath
- Apple trees
- Pear trees
- Some cultivars and species of strawberry
- Some cultivars and species of eggplant, tomato, and potato
How to Treat Verticillium Wilt
You can’t treat verticillium wilt. Once a plant is infected, it will eventually die. The best course of action is to remove affected plants to prevent the spread of the disease.
Perennials, trees, and shrubs may be kept alive with proper care, but you’ll have to weigh the pros and cons of doing so.
Do you risk infecting other plants in your garden by keeping this plant alive? Then you might consider disposing of the infected plant. If you decide to keep the plant alive, remove affected plant material and dead branches.
If you’ve discovered the presence of verticillium wilt in your garden, that means the fungus is living in your soil. It’s possible to kill off the fungus with the use of solarization techniques, but it’s not a guarantee that the process will rid your soil of verticillium wilt completely.
Solarization is a useful technique that utilizes the power of the sun to kill bacteria, pests, weeds, fungi, and other harmful pathogens living inside garden soil.
By covering affected garden areas with transparent plastics, it’s possible to heat up the soil enough to kill harmful microorganisms. It’s best to solarize patches of soil in the summer when the sun rays are the strongest, which means you’ll be cut off from accessing that particular part of your garden during the process. Keep that in mind when planning during the spring.
It takes up to six weeks to complete the solarization process.
Now You’re Armed and Ready
Have you ever had to deal with this frustrating garden disease? What was your experience like with verticillium wilt? Did it affect your edibles or other plants in your yard?
How did you go about dealing with the problem? Let us know! We want to hear about your experience.