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How to Identify and Control White Mold on Plants and Vegetables

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Prevent White Mold Fungus in Your Garden!

Catherine Boeckmann
Pest Type
Plant Diseases

Have you ever noticed dense white fuzz at the base of your plants—or have you seen mold symptoms on stems, leaves, or blossoms? Learn about white mold—a fungal infection—and how to prevent and control this plant disease.

What Is White Mold?

White mold, also known as sclerotinia, is a fungal disease that affects more than 360 different garden plants, including beans, peas, lettuce, and members of the cabbage family. White mold on tomato plants is sometimes called timber rot. 

Mold symptoms appear on blossoms, stems, leaves, and pods with water-soaked spots. Leaves wilt, yellow, and die, and pods may rot.

The host crops and plants are most susceptible during flowering, but young seedlings are also very vulnerable. White mold typically infects the plants early in the spring or summer and then develops unnoticed for a while. 

White mold fungus spreads spores in cool weather, which can infect other plants through the wind. This is why it is so important to catch white mold and destroy the infected plants quickly to stop the spread of the fungal plant disease.

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Identification

How to Identify White Mold Damage

White mold symptoms (signs of sclerotinia) tend to vary depending on the environment and type of plant, but here are some of the most common ones:

  • The stem might first appear to have a water-soaked part. At this point in the infection, the plant will look healthy from above.
  • Wilting of individual stems, especially at the base, with tan discoloration.
  • Infected stems may appear to have tan to dark brown lesions on them. From these lesions, a dense, cotton-like growth will form under conditions of high humidity.
green beans affected with white mold
White mold takes over a bean plant with its dense cotton-like growth.
Photo Credit:
Gardening Products
Control and Prevention

How to Control White Mold

  • As soon as you notice any diseased plants, destroy them immediately.
  • If your soil is infected, remove as much of it as you can and replace it with clean soil.
  • You can use a barrier, such as plastic or mulch, to cover the infected ground to prevent the spread of the disease.

Prevent White Mold

  • Be sure to use well-drained soil and space your plants properly to avoid crowding. Also, remember to avoid areas with poor air circulation.
  • When watering your plants, try not to water the tops of them. Or water the plants early in the day so they have the chance to dry before nightfall. Learn more about the best times to water your plants.
  • You can also spray your plants with an approved fungicide to help prevent infection. Spray the plants right before they bud, then spray again a week later.
  • Control your weeds. Weeds can host this disease and spread it to your plants.
  • If possible, remove all crop residue after harvesting. If residue is left, this disease may develop in it. White mold spores are long-lasting, so they will survive the winter if given the chance.
Plant Disease
About The Author

Catherine Boeckmann

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s ÃÛÌÒÁµÈË found each other. She leads digital content for the ÃÛÌÒÁµÈË website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann
 

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Comments

Hi, Lea: Meet powdery mildew. Before doing anything drastic, just try washing it off with a water spray. (Some folks say plus milk, and/or plus baking soda, etc.; we say keep it simple, at least to start.) Do it in the morning so that the leaves have time to dry out before the humid part of the day, humidity being the main culprit, not water itself.

tanya parker (not verified)

10 years 8 months ago

hello, your site and info has been super helpful to me. I am growing quite a few things from seed right now inside and everything seems to be going great, only problem is white mold in some soil and on the containers I'm growing them in. Its not on the actual sprouts though. Any idea what I can do or if I leave it will it ruin all my plants? I'm growing veggies, fruit and herbs. Like I said though, they seem to be growing like crazy.

It sounds as if you may be watering too frequently. Make sure that you aren't saturating the soil; let it dry out and then deeply water and then let it dry out again between waterings. Take the seedlings off any watering trays so they're not wet on the bottom; let them drain and put on a cloth. You can scrape off the white mold; if it gets too bad, you might need to replant the seedlings in clean soil. You could also consider an anti-fungal product; ask your garden center. Finally, some readers suggest adding a little sand and others say sprinkling with cinnamon helps!

leniya (not verified)

11 years 4 months ago

im scared that my lettuce plants will get white mold what is the best pesticide for this mold i live in detroit michigan and im making a garden in my grandmothers back yard and im choosing a moist area in her back yard what am i supposed to do when my plant gets white mold do i throw it away or keep it please answer my qustion i would kindly like an answer

To prevent white mold, avoid wet soil or overwatering. Just keep soil moist.
Use raised beds.
Create furrows in the soil for watering or irrigation so that the water doesn't just flow all over the bed surfaces.
Do not water from overhead and get the plants wet; water at the soil line.
Space plants extra far apart to allow good air circulation.
Remove and destroy entire infected plants and crop residues as soon as you see any signs of mold.
Hope this helps.
 

Rosangela de Azevedo (not verified)

11 years 4 months ago

Kathy Joyce,

Try watering early morning.
When you water at night, a lot of water remains around the plant and its root. It facilitate rotting and development of diseases.

Kathy Joyce (not verified)

11 years 5 months ago

The flowers on both my petunia plants have polka dot-looking white spots on each bloom. They are separated from each other the length of the small patio. I did water each evening, they have drainage holes. What happened?

Kathy Joyce (not verified)

11 years 5 months ago

Thanks for answer to petunia white dots,

Lad (not verified)

11 years 5 months ago

On my sunflowers, there is a sticky white drippy looking substance between the main stem and the leaf stem. What is this and how should I treat it? And, is it contagious to the garden generally?

Every once in a while we don't have a clear and specific answer and this is one of those times, Lad. You do not indicate where you are but it seems that the sticky white substance may not be from the plant itself but from whiteflies or aphids.
Now you wonder, what to do? If indeed this is the case, ideally, you would want to encourage "good bugs" (some wasps, predatory mites, black ladybird beetles, for example, depending on your area) into your garden to eliminate these pests rather than apply insecticides, which might destroy any good bugs that are present. A good bug welcome mat can not be put out in a day; it's often a gradual thing that can be accomplished by bringing in other plants.
To have a better idea of what you're dealing with and how to eliminate it, we suggest that you contact your local agricultural extension service. They would be more familiar with specific conditions in your area. Hope this helps—Best wishes!