Powdery mildew is a common fungal disease that can affect many plants, including African violets. It shows up as a white, powdery coating on the flowers, stems, and leaves. Powdery mildew is usually not fatal, but if it is not treated, it can have a big effect on the health and look of African violets. This complete guide will show you how to find powdery mildew on your favorite African violets, treat it, and keep it from happening again.
What Causes Powdery Mildew on African Violets?
Powdery mildew is caused by fungal spores that thrive in warm, humid environments with poor air circulation. Fluctuations in temperature and low light exposure can also contribute to outbreaks. The spores germinate on the plant’s surface and send rootlike growths called haustoria into the plant’s cells, from which they leach nutrients. The fungus then covers itself with the iconic white “powder” – actually chains of spores – which allows it to spread quickly to surrounding leaves and plants.
How to Identify Powdery Mildew on African Violets
Powdery mildew is easy to recognize on African violets. Watch for these key signs:
- White or gray powdery coating on leaves, stems, and/or flowers
- Powdery coating starts off patchy but spreads to cover entire affected areas
- Leaves yellowing or browning
- Flowers dropping off
- Slowed growth
- Spots or streaks on flowers
Carefully look at the stems, flowers, and both the top and bottom of the leaves to find the powdery fungus. Powdery mildew is sometimes mistaken for botrytis, which is another fungal disease. To tell them apart, powdery mildew has fine, even growth while botrytis has fuzzier, spottier growth.
Treating Powdery Mildew on African Violets
If you catch powdery mildew early, treatment can help restore your African violets’ health. Here are some effective powdery mildew treatments:
-
Isolate affected plants to prevent spread Discard severely infected plants
-
Improve air circulation with fans; avoid overcrowding.
-
Trim off badly affected leaves and flowers. Remove debris carefully to avoid spreading spores.
-
Wash leaves gently with water to remove spores. Avoid wetting foliage.
-
On the stems and leaves, use solutions of neem oil, milk, vinegar, hydrogen peroxide, or baking soda. May require multiple applications.
-
If you need to, you can buy fungicides that have sulfur, neem oil, or chemicals like benomyl or captan in them. Follow label directions closely.
-
Maintain warm, stable temperatures around 70°F to discourage fungal growth. Avoid drafts and temperature shifts.
-
Reduce humidity to 60% or below.
-
Improve light exposure if low light is an issue.
With vigilant treatment, you can get powdery mildew under control and restore your African violets to health. Be sure to continue preventive care.
Preventing Powdery Mildew on African Violets
While powdery mildew treatment can be effective, prevention is always better to avoid stressed, damaged plants. Here are some key powdery mildew prevention tips for African violets:
-
Site plants properly – ensure good air circulation, avoid high humidity and overcrowding, maintain consistent warm temperatures around 70°F.
-
Water carefully – don’t splash leaves, allow pots to dry out between waterings.
-
Ensure adequate light – African violets need 12-14 hours of bright, indirect light daily.
-
Remove spent flowers/leaves – prune promptly to improve air flow.
-
Disinfect pots, tools – use a 10% bleach solution to kill lingering fungal spores.
-
Use fans judiciously – gentle air circulation helps prevent fungal and bacterial diseases. Avoid drafts.
-
Limit high-nitrogen fertilizer – promotes fast, weak growth prone to mildew. Moderate feeding with balanced fertilizer.
-
Isolate new plants – quarantine and monitor for diseases before introducing to your collection.
-
Scout regularly for problems – catch powdery mildew early before it spreads.
With proper growing conditions and care, you can help your African violets thrive and avoid powdery mildew issues. Be vigilant for early signs and take prompt action at the first hint of powdery growth. Stay on top of prevention, and you can continue enjoying the unique beauty of healthy African violets.
Cross-Contamination With New Plants
If you’re providing good care for your African violets, it’s unlikely that disease and fungus will develop. However, there is a risk of introducing disease and fungus anytime you bring new plants into your home.
Any plant, not just African violets, should be carefully checked out before being brought inside with your African violets. When a disease or fungus spreads to other plants, it can be hard to stop it and save your plants. Do not bring any plant that shows signs of disease or fungus into your home.
Some people even go so far as to keep new plants in a separate area for a period of time just to make sure everything is fine. It might seem like too much, but if you have a lot of plants or plants that are hard to replace, it makes sense to keep any new plants in a separate area before adding them to your collection.
African Violet Diseases Final Thoughts
Although there are a lot of diseases that can bother African violets, most of these diseases don’t occur too frequently (with the exception of ring spots, which are easy to avoid).
Take good care of your African violets to prevent disease and fungus from developing in the first place. As a quick reminder, here are a few of the best ways to keep your plants from having problems:
- Don’t overwater your African violets. Let the soil dry out between waterings.
- Keep your tools and containers sterilized.
- Make sure your African violets have adequate air circulation.
Also, carefully inspect any new African violets and isolate them to watch for signs of fungus or disease before bringing them into your home with other African violets.
Hopefully you won’t ever have to deal with diseases infecting your African violets. If you do have an African violet develop a disease, make sure to isolate it right away and keep it isolated while you treat the disease.
If you aren’t able to save an African violet that’s been infected, don’t feel too bad; all houseplant owners lose a plant from time to time. On the bright side, you’ve learned more about what not to do in the future, and you now have room to add another plant to your collection
African Violets – POWDERY MILDEW – Symptoms, Treatment, Prevention
FAQ
How to treat powdery mildew on African Violet?
Simply brush off the mildew with a wet brush, cleaning the brush in methylated spirits after finishing and allowing it to dry. Wash the leaves with mildly warm running water (only in the early part of the day). Blot left-over water away from the centre of the plant.
What kills powdery mildew immediately?
Potassium Bicarbonate: This is like baking soda, but it destroys powdery mildew once it’s there, which is what makes it special. Potassium bicarbonate is a contact fungicide which kills the powdery mildew spores quickly. In addition, it’s approved for use in organic growing.
Can a plant with powdery mildew be saved?
Luckily, there are effective powdery mildew treatments that can help fight the disease. Powdery mildew can be treated early on with fungicides including potassium bicarbonate, neem oil, sulfur, or copper. Home remedies like baking soda and milk can work as successful treatments when applied properly.
What causes white powder on African violets?
Powdery Mildew is caused by the Oidium fungus which thrives under conditions of high humidity and poor air circulation, especially after sudden changes in temperature. Such conditions often occur in spring when precipitation is high, and hot days alternate with cold nights.