Before we look at the best remedies, let me clarify briefly what powdery mildew is (and what it isn’t). Powdery Mildew is a kind of fungal disease that thrives in different plants. It is the most common and easily recognized plant disease, especially when compared to other fungal diseases that may be hard to tell from each other.
Powdery mildew is a widespread fungus on plants, trees, fruits, and vegetables, and its symptoms are quite distinctive. It is prevalent in warm, dry weather. It does not spread so well in cooler, rainy areas. Hence, it has a chance to survive in winter seasons within the buds and tissue of the host plants.
Various plants are immune to this kind of fungal disease, however, some are more susceptible than others. The fungus develops in moderate temperature, low humid environment and overwinters in the soil. The lower leaves of the plants are the most affected, but the mildew can develop on any above-ground part of the plants.
White spots, as if dusted with flour
The powdery mildew first appears as white spots, just as if you dusted your beloved succulent with flour, or refined powdery sugar :). It can appear in stems, leaves and sometimes in fruits. The white spots can take over to leaves and to the affected area as well.
Powdery mildew may disfigure the plants’ leaves, buds, and growing tips. The plant that has powdery mildew can affect the other plant through the wind, insects and splashing water. The infection is uncommon during the lengthened rainy season and extreme heat. As the mildew spread, the leaves become yellow and wit, eventually, the entire branch dies.
The powdery mildew is caused by high humidity. In some cases, the fungal growth can be temporarily removed by rubbing the leaves. Infections may occur when they connect to suitable hosts and especially when environmental conditions are perfect. There are other effects of powdery mildew that are not readily visible. Fertilize to optimize the plant and also the plant health, but avoid over-fertilize with nitrogen as it enlivens young, succulent growth which is more susceptible to infection.
Taking away the plant’s nutrients
Powdery mildew can take away the plant’s nutrients therefore the plant can become weaker, less bloom and it slows down the plant’s growth. Eventually, if you do not treat it, powdery mildew can kill the plants.
When it has covered the plants’ leaves, the photosynthesis does not work as it should, and the infected leaves may fall. That’s what you should try to avoid at all costs. The ideal condition for powdery mildew to attack the plants and cause most damage is during the late spring or early summer when evenings are still cool.
Succulents that have a severe infection must be monitored closely the following spring so that if infections reoccur, they can be treated immediately. Powdery mildew has a various genus on each plant, and each succulent. Let’s have a look at most common ones.
Powdery mildews in various plants
- Wheat, barley and other cereals – Blumeria graminis
- Legumes – Microsphaera diffusa
- Grape – Erysiphe necator (or Uncinula necator)
- Onions – Leveillula taurica
- Apples and pears – Podosphaera leucotricha
- Lilacs – Microsphaera syringae
- Strawberries – Podos aphanis
- Tree leaves – Sawadaea tulasnei
- Oregon grape – Erysiphe berberidis
- Arabidopis – Golovinomyces orontii
How to prevent your succulents from succumbing to powdery mildew
Fortunately, there are many options to prevent this fungus. Let me list the major ones:
- Choose a succulent or plant that is resistant and tolerant to powdery mildew.
- Avoid watering succulents or plants from overhead to reduce humidity.
- Selectively shear the overcrowded to increase the circulation of air, this also helps to reduce humidity, and consequently a chance of developing a fungal infection.
- Always sanitize the pruning tools, to make sure you do not bring the infection from one plant to another.
- Remove the affected foliage from the plant and clean up the fallen debris on the ground.
- Spray your plants with fungicides, ideally the ones with copper, such as this great fungicide.
- Water the succulents in the morning, so plants have a chance to dry during the day, and do not stay humid for the night to attract fungi.
- Avoid placing susceptible succulents to humid and shady areas.
- Avoid over-fertilizing the succulents with nitrogen.
- Use healthy planting stock.s
- Avoid chemicals in your garden as much as possible.
- Place the succulents in a fitting place so they can get some direct sunlight.
- Make sure soil drained properly before watering again. If you do not do it, a soil can become a breeding ground for disease-causing organisms.
Ten organic treatments for powdery mildews
- Potassium bicarbonate – is an effective and safe treatment that kills spores. It has the unique advantage of eliminating powdery mildew once it’s there. It is a contact fungicide that kills the spores of powdery mildew quickly.
- Milk – another effective way to get rid of powdery mildew. As the milk is hit by the sun, free radicals will form that will, in turn, kill the fungus.
- Neem oil – is from the seeds and fruit of neem tree. It is powerful enough to kill powdery milk in less than 24 hours.
- Vinegar – it is very effective in killing powdery mildew because of the acetic acid in apple cider vinegar. But, be careful to not make the mixture too strong as the acidity can burn succulent leaves.
- Baking soda – similar to potassium bicarbonate, baking soda has a pH level of 9, enough to kill the fungus. This is the homemade organic treatment for spores of powdery mildew.
- Garlic – has high sulfur that can kill powdery mildews.
- Sulfur – it is a natural product that can control and prevent powdery mildew
- Copper fungicides – it is very effective when it comes to killing fungus but it is very important to follow instructions closely.
- Mouthwash – if this can kill bacteria in our mouth, certainly the fungal spores of powdery mildew are no match for its properties.
- Water – it washes off the spores before they have time to be embedded but it is only temporary. Spores may form again in plants.
5 Best fungicides for powdery mildew
If the free methods discussed above did not work, you use the following fungicide for your succulents:
- Bayer Advanced 701270
- Wondercide All Purpose-Organic Insect Control
- Spectracide Immunex Fungus Control
- Wondercide Eco Treat-Powdery Mildew Killer
- Ferti- Lome 11380 Liquid Fungicide Spray
* Please note that there are affiliate links. If you purchase one of the products I may earn a small commission at no extra cost to you. Such commissions help me to continue this blog.
Plants and fruits susceptible to powdery mildew
- Begonias, Sunflowers, Chrysanthemums
- Dahlias, Roses, Zinnias
- Melons, Zucchini, Squash
- Lettuce, Cucumbers, Potatoes
- Parsley, Pumpkins, Grape
- Peppers, Tomatoes, Various tree fruits
Powdery mildew can be caused by a variety of reasons, and sometimes you are just unlucky and your plants get it. When prevalent, this innocently looking fungus may prove to be the biggest problem for the gardener.
Powdery mildew won’t infect humans but it can certainly kill succulents and other plants if you do not treat it. You should always take precautions, because if you don’t the chances are high that you won’t avoid seeing your plants infected.
Direct sunlight helps to kill the spores of powdery mildew before they can spread to plants. As the mildew progress, the spots are getting larger and compact as large numbers of asexual spores are formed, and the mildew may spread up and down the distance of the plant. As situation gets serious, direct sunlight won’t be enough, and you will have to use one of the remedies I described in this article. I sincerely hope you will succeed, and enjoy the succulents in their full beauty. My also interest you: