Powdery Mildew on Succulents

Succulents have a high tolerance for fungi that cause leaf spots, but they can also develop fungal diseases. The probable reason for this is a change in natural habitat. A common fungal infection among succulents is powdery mildew. It is easy to identify and has distinctive symptoms such as pale yellow and white powdery spots. 

Powdery mildew on succulents: What it is, treatment and prevention 

Powdery mildew is prevalent in warm and dry weather, and does not spread well in cool and rainy environments. Certain plants are immune to this fungal infection, but succulents can become prone to it. The fungus rapidly develops in a humid environment with moderate temperatures. Most often, the most affected parts are the lower leaves, but above-ground parts are also susceptible. 

It is often characterized as white spots and affected succulents look like they are dusted with flour. The fungus could appear on the stems, fruits and leaves. It could eventually disfigure the leaves, buds and growing tips and could also affect other plants through insects, the wind and even splashing water. As the fungus spreads, the leaves turn yellow and become wilted until eventually, the whole branch dies.

Powdery mildew may be caused by high humidity and in certain cases, it can be temporarily removed by rubbing the leaves. It can take away the plant’s nutrients and weaken it, resulting in lesser blooms and stunted growth. The fungus could even kill your succulents.  

Treatment for powdery mildew on succulents 

These are the common organic treatment options for powdery mildew:

  1. Potassium bicarbonate: It effectively kills powdery mildew spores. 
  2. Milk: It gets rid of the fungus once it is hit by the sun and free radicals start to form.
  3. Neem oil: It kills the fungus in less than a day. 
  4. Vinegar: The acetic acid effectively kills the fungus, but make sure not to use a strong mixture to avoid burning the leaves. 
  5. Baking soda: It has a high pH level that kills the fungus, just like potassium bicarbonate.
  6. Garlic: It kills powdery mildew because of the high sulfur content.
  7. Sulfur: It controls and prevents the growth of the fungus.
  8. Copper: It is an effective treatment but you need to follow strict instructions.
  9. Mouthwash: Another organic way to eradicate the fungus.
  10. Water: It washes off the spores but only works temporarily. 

Aside from organic treatment,  you can also use fungicides to treat powdery mildew on succulents. Some of the recommended fungicides include Bayer Advanced 701270 and Spectracide Immunex Fungus Control. 

How to use baking soda for powdery mildew treatment

Mix one tablespoon of baking soda and one-half teaspoon of liquid, non-detergent soap with one gallon of water. Spray the mixture on affected leaves. See to it that the plant is watered well before application of the baking soda mixture. Do not apply the treatment during the daytime as the mixture can cause sunburn. It is best to test it on a few leaves first.

Prevention for powdery mildew on succulents

Here are ways to prevent powdery mildew on succulents:

  • Opt for succulents that are resistant and tolerant to the fungus.
  • Do not water succulents from overhead to minimize humidity. 
  • Shear overcrowded plant parts to increase the circulation of air and reduce humidity. 
  • Sanitize your pruning tools. 
  • Periodically spray your succulents with fungicides. 
  • Remove affected plant foliage to prevent the spread to nearby plants.
  • Your watering routine should be in the morning so the plants, and especially the soil, can dry out during the day. 
  • Do not place susceptible succulents in shady and humid areas. 
  • Avoid over-fertilizing with nitrogen.
  • Utilize healthy planting stocks.
  • Avoid chemical application as much as possible.
  • Make sure that succulents have some access to direct sunlight.
  • See to it that the soil drains properly.

Conclusion 

Powdery mildew on succulents could pose a great threat and even kill your plants. Aside from fungicides, various organic treatments are effective in eradicating the fungus, such as baking soda, neem oil and copper. It is ideal to apply preventative measures as mentioned above to ensure the health of your succulents. 

Image: istockphoto.com / alexander ruiz

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