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Marigolds are common companion plants, which appear to repel many pest insects. They are fairly resistant to insect issues, but diseases in marigold plants are an occasional problem. The most prevalent diseases are fungal and affect stems, leaves, and roots. Marigold plant diseases are relatively easy to diagnose and treat, however. In fact, most can be cured by using different cultural methods.
Among the most common marigold diseases are blights, rots, and mildews. Usually, these types of diseases show up when conditions are wet and warm, and fungal spores are rampant. In most cases, simply discontinuing overhead watering can stop the formation and spread of spores. As mentioned, fungal marigold plant diseases occur most often. These might be Aster yellows, wilt, and stem rot, collar rot, flower bud rot, and damping off when in the seedling phase. Fungicide applications can help in controlling diseases of marigold caused by fungus along with avoiding overhead irrigation. Powdery mildew is another fungal disease that affects all kinds of plants. It is recognized by a powdery white film on leaves and other surfaces. Spraying a mixture of baking soda, water, and a touch of dish soap is an effective weapon. Correct timing when watering plants will allow the moisture to dry on foliage and is another effective strategy to avoid fungal diseases like this. Additionally, ensure that you have correct drainage in your containers and beds.
As an avid gardener and blogger, I often get questions from readers about dealing with mold on their African marigold flowers. Marigolds are such cheerful additions to any garden, with their bright golden blooms lighting up flower beds and borders. However, these plants can be susceptible to mold growth, especially in humid conditions. If left untreated, mold can damage marigold plants and ruin their ornamental value.
In this comprehensive guide I’ll walk you through the causes identification, prevention, and treatment of mold on African marigold flowers. Whether you’re a beginner or experienced gardener, you’ll learn straightforward techniques to banish mold and keep your marigolds healthy and thriving.
What Causes Mold on Marigolds?
Mold is caused by various fungal organisms that thrive in warm, moist environments. Common culprits for mold on marigolds include:
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Powdery mildew – Recognizable by its white, powdery coating on leaves and flowers.
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Downy mildew – Causes yellow or brown spots with a fuzzy texture
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Botrytis or gray mold – Leads to fuzzy grayish mold, especially in cool, wet weather.
Overwatering and poor air circulation create optimal conditions for these mold fungi to grow and spread. High humidity levels can also contribute to mold issues on African marigolds.
How to Identify Mold on Marigolds
Learn to recognize the early signs of mold infestation on your marigolds:
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White powdery substance on leaves and flowers – indicative of powdery mildew.
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Yellowing leaves with brown fuzzy spots – a symptom of downy mildew.
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Gray fuzzy mold on flowers and stems – caused by Botrytis.
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Distorted, yellowing or dropping leaves and flowers.
Acting quickly at the first signs of mold is key to controlling it before major damage occurs.
6 Tips to Prevent Mold on Marigolds
Stopping mold before it takes hold is the best approach. Here are proactive tips to reduce mold risk:
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Space plants out for better airflow.
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Water early in the day so leaves dry quickly.
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Use drip irrigation or water at the base to keep foliage dry.
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Remove weeds and dead leaves/flowers which can harbor mold spores.
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Prune plants to improve air circulation within the canopy.
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Choose mold-resistant marigold varieties.
How to Get Rid of Mold on Marigolds
If mold manifests despite prevention efforts, take action right away with these treatment methods:
Non-Chemical Options
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Spray a baking soda solution (1 tbsp baking soda + 1 quart water) weekly. The antifungal properties help combat mold.
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Apply neem oil solution weekly – it smothers fungal spores naturally.
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Increase air circulation with fans (for indoor plants) to quickly dry foliage.
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Remove and destroy severely infected plant parts.
Chemical Fungicides
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Copper-based fungicides prevent the spread of mold when applied at first sightings.
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Products with chlorothalonil or mancozeb as active ingredients are also effective against common marigold molds.
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Always follow label directions carefully when using commercial fungicides.
Marigold Care Tips to Minimize Mold
Alongside treatment, optimize care of your marigolds to discourage mold growth:
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Water early in the day, avoiding wetting foliage.
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Use drip irrigation or water at soil level rather than overhead watering.
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Space plants 12-15 inches apart for airflow.
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Provide at least 6 hours of direct sunlight daily.
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Remove spent flowers and leaves regularly.
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Ensure soil drains well and does not remain soggy.
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Rotate marigolds to different areas annually to prevent soil pathogens.
Other Diseases in Marigold Plants
While many issues can be caused by inadequate nutrients, nutrient excesses in soil can also lead to many plant ailments. Leaf burn, where the tips of leaves and new growth yellow and die, is the result of surplus boron, manganese, or molybdenum. When using fertilizer, be certain your soil needs the amount of nutrients it contains. Soil levels for boron should be 55 parts per million, manganese 24 ppm, and molybdenum just 3 ppm. It may be necessary to perform a soil test to determine what nutrients are already in the soil. Marigolds are not tolerant of low pH soils. This causes manganese or iron toxicity, which will cause leaves to brown and speckle. If pH is too low, you will need to amend the soil with lime for the next years plants. Bacterial leaf spot is another disease in marigold plants. Unfortunately, the entire plant must be destroyed to prevent spreading the disease.
Controlling Diseases of Marigold
Hindsight is 20/20, but prevention is a crucial part of the strategy.
- Most marigold plant diseases will be due to fungal spores, so correct watering is key.
- Removing infected plant material can also help limit the spread of disease.
- Amend soil with well-rotted compost. If you have heavy clay soil, add sand or other grit to loosen the soil.
- Use containers that drain well and avoid using saucers, which can catch water and cause root rot.
- Use pathogen free potting mixes or sterilize your soil before planting marigolds. If you had an infected plant in the past, use bleach to clean containers before installing any new plant species.
- Choose French and dwarf varieties of marigold, rather than the African species.
Fortunately, problems with marigolds are rare and easily fixed, leaving you with happy plants and a season of golden blooms.
How to Control Pests & Disease for Marigolds : Grow Guru
FAQ
How to treat marigold fungus?
How do you get rid of powdery mildew on marigolds?
What is the white fuzz on my marigolds?
How do you get rid of mold on flowers?
How do you get rid of marigold fungus?
Most marigold plant diseases will be due to fungal spores, so correct watering is key. Removing infected plant material can also help limit the spread of disease. Amend soil with well-rotted compost. If you have heavy clay soil, add sand or other grit to loosen the soil.
How do you treat powdery mildew on African marigold plants?
Identification: Look for white powdery spots on the foliage of the African marigold plant. The affected leaves may also become distorted or yellowed. Treatment: To treat powdery mildew, remove and destroy any infected plant parts immediately. Make sure to improve air circulation around the plants by spacing them properly.
How do you treat root rot on African marigolds?
Treatment: To prevent root rot, ensure that your African marigolds are planted in well-draining soil. Avoid overwatering and water at the base of the plants to keep the foliage dry. If root rot is detected, remove the affected plants and replant in fresh soil.
What causes gray mold on African marigolds?
Botrytis blight, also known as gray mold, is a fungal disease that affects African marigolds, especially during cool and wet weather conditions. It manifests as fuzzy gray mold on the flowers, stems, and leaves of the plant. Identification: Look for brown spots on the petals of the flowers that quickly turn into fuzzy gray mold.