My Marigolds Have White Mold on Them


Marigolds, also known as Tagetes spp., are annuals that need little care and can be grown in the United States Department of Agriculture plant hardiness zones 2 through 11, according to the Missouri Botanical Garden. They provide a vibrant splash of orange or yellow colour to the landscape. These flowers are prone to several marigold issues that might cause mould, such as powdery mildew, white mould, and botrytis blight, which are all types of mould that affect marigolds.

Marigold Powdery Mildew

A common fungal disease known as powdery mildew is responsible for the growth of grey or white mould on your marigold plants. The University of Minnesota Extension warns that infected leaves may grow irregularly and may turn yellow if the infection progresses. At the conclusion of the growing season, the mould may produce a number of little orange or black balls. Chasmothecia is the name given to these balls, which serve the function of shielding the fungus during the colder months.

Spores disperse via the air and may infect other plants in your garden if they come into contact with them. Powdery mildew infections are often moderate and do not have a significant impact on the development of your marigold plant. It is important to refrain from over-fertilizing with nitrogen and over-watering, both of which may promote the development of fungi. Maintain a healthy distance between your plants to ensure adequate circulation of air.

When dealing with a serious case, further therapy can be required. Fungicide treatment of plants should begin in the spring, well before the appearance of powdery mildew, and should be repeated as necessary throughout the year. Apply the fungicide by following the directions on the label of the product. Closely monitor your plants and remove any leaves that seem to be diseased straight away.

White Mold Infection

The fungus Sclerotinia sclerotiorum is responsible for the illness known as white mould. According to information provided by the University of Minnesota Extension, it results in the development of a fluffy white mould on affected leaves and stems. In addition to this, the region around the infection may exhibit signs such as withering leaves and dry, brittle stems that are a tan hue. Stems that are infected may produce sclerotia, which are dark, tiny formations that are rather rigid.

Because the mould spores may live for up to five years in the sclerotia, this is a difficult disease to eliminate completely from your garden. When the conditions are right, the spores will germinate into mushrooms, which will then produce more spores.

This infection is not treatable in any way that is successful. Take out of the garden all of the plants that are diseased. You have the option of either burning the sick plants or burying them at a location that is a significant distance from where you want to plant. When transplanting, make sure to provide plenty of space between the new plants and the old ones to ensure that the foliage stays dry. Reduce the amount of water that is irrigated and the amount of moisture that is present.

Other Marigold Problems

Another kind of fungus that has the potential to infect your flower is botrytis blight, which affects marigolds. According to the Missouri Botanical Garden, the mould that appears on your plant as a result of the illness appears when the weather is chilly and humid. Additionally, it causes dark stains to appear on flowers and flower buds, as well as promotes aberrant development of the blooms.

As quickly as possible, cut off and remove the diseased portions of the plant. Take precautions to prevent situations in which fungus may flourish, just as you would with other fungal infections. Spread the plants out farther from one another to avoid having too many in close proximity. It is important to refrain from over-fertilizing since new growth is more prone to infection when exposed to high nitrogen levels. Last but not least, avoid overwatering the plant or getting the leaves wet since doing so will produce circumstances that are ideal for the growth of fungus.

If the infection is really bad, you may also try spraying the plant with a fungicide once every ten days to control it. Copper, sulphur, or thiophanate methyl are a few examples of fungicides that may be used. Always apply the product in accordance with the directions provided on the packaging.