Succulents grow naturally in hot and dry places and are endemic to areas such Central America, Africa, and South America. While they are known as hardy plants that can survive with minimal amounts of moisture, they are also prone to diseases. Read on for some important details on succulent diseases and common treatment options.
Common Succulent Diseases
These are some of the most common diseases in succulents:
Fungal diseases or infections
Succulents tend to develop fungal infections when they are removed from their natural habitats. The main culprit is a change in conditions since succulents thrive in a dry climate. Too much moisture can lead to fungal attacks.
These are some common fungal infections among succulents:
1. Sooty mold
This is also called the black mold and is considered the least damaging fungi. It is caused by the presence of aphids, whiteflies, scales, and mealybugs. The insects produce honeydew that the sooty mold feeds on.
Treatment: To eradicate sooty mold, your succulents should be free from insect infestations. Spray the plants with rubbing alcohol or apply neem oil.
2. Grey mold
Grey mold is also called Botrytis cinerea, an infection that is easy to identify. It forms grayish-brown spore masses on the leaves and flowers of succulents and often spreads when the weather is cold and wet during early spring and summer. It spreads quickly and chooses damaged or dying succulent tissues.
Treatment: Use fungicides during the early stages, but if the infection is serious, you will need to cut the affected areas and burn off the damaged tissues. Avoid watering the affected plants from the top so they can dry out between watering. Do not leave stubs when taking cuttings.
3. Leaf spots
This fungal infection disfigures succulents severely. If there is a heavy infection, it can spread to other plants. However, despite the appearance of it, it does very little damage to succulents.
Treatment: Do not use a fungicide if you notice shallow tan lesions or spotting on the affected plants. You can replace the plants, but since the fungal infection does little damage, the affected plants will eventually outgrow and tolerate it.
4. Fusarium wilt
This fungal infection is caused by Fusarium oxysporum, a pathogen. It prevents succulents from taking up water and causes wilting, yellowing, and death. The fungus penetrates the plants through the roots and reproduces in the vascular tissues, which get blocked. This means the plant cannot absorb water anymore. You will notice brown streaks if you cut the leaves of infected plants.
Treatment: Water the affected plant sparingly to discourage further fungal growth. Use sanitized tools and provide enough feeding to encourage the growth of new and healthy tissues.
The infection is caused by fungi of the genus Colletotrichum and affects many cacti and succulents. Your plant may be infected with this fungi if it has moist, tan-colored rot with red, pink, or orange pustules.
Treatment: Remove and destroy affected leaves and avoid reusing the contaminated soil. You may also use a copper fungicide to destroy the remaining fungal bodies.
6. Root and crown rots
This infection is caused by the fungal pathogens of the genus Phytophthora. The symptoms of this fungal infection are not identifiable during the early stages, which makes it hard to differentiate from other fungal diseases. Affected succulents become wilted and stressed, change their colors, and eventually die because of a slow rot that develops upward from the soil level.
Treatment: This infection does not respond well to treatment. The best you can do is to replant your succulents in well-draining soil and avoid overwatering them.
7. Powdery mildew
This disease is caused by the bacterium Sphaerotheca and usually affects herbaceous plants and succulents. Symptoms include scabby or corky areas on the leaves.
Treatment: Treat this infection by applying fungicides like Triadimefon. Home remedies include milk, baking soda, garlic, and compost tea.
Succulents are also prone to viral infections which spread through insects that feed on their sap. Insects and pests should be eradicated so as not to spread the viruses. Keep your grafting knives disinfected at all times. Signs of viral infections include stunted growth and abnormal shoots overgrowth. Affected plants are usually discarded since there is no specific treatment for the infections.
An example of a common bacterial infection among succulents is called bacterial soft rot. This infection is caused by the pathogen Erwinia. Signs include soft and mushy plant tissues, as well as the collapse of stems and branches. This is also called the damping-off disease and usually affects small seedlings. Unfortunately, there is no cure for this disease; affected succulents should be discarded. Do not overwater your plants and provide adequate air circulation to prevent this disease.
Aside from diseases and infections, succulents can also suffer from nutritional deficiencies. The soil’s pH levels can affect their ability to absorb minerals. You can reduce the alkalinity by adding vinegar to the soil.
According to Saddleback College, iron deficiency is common among succulents and causes them to turn yellow. Adding vinegar to the soil enhances the availability of iron according to reports done by The Vinegar Institute. Too much nitrogen in the soil can also upset the pH balance, preventing flowering and causing plants to turn darker green.
Poor care of succulents can also lead to disease-like conditions such as desiccation, sunburn, overwatering, and etiolation, which is characterized by long, weak stems and smaller leaves. These conditions can be prevented by watering your plants correctly, providing proper ventilation, and giving access to just the right sunlight.
Succulents are hardy plants, but they are also prone to infections and diseases. They tend to develop bacterial, fungal, and viral diseases as well as deficiencies and disease-like conditions. To ensure that your plants are healthy, learn what you can about proper succulent care from plant experts and succulent growers. Most importantly, make sure that you do not overwater your plants and that you use well-draining soil.
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