How Do You Treat Powdery Mildew On Japanese Maples: 3 Ways

How do you treat powdery mildew on Japanese maples? If you don’t have any idea about doing this, just read through and we’ll help you.

Powdery mildew is very common on trees, woody ornamentals, and even on flowers. Almost no type of plant is immune to it unless those hybrid plants which are bred specifically to resist mold and mildew.

how do you treat powdery mildew on japanese maples


What Is Powdery Mildew?

Powdery mildew is a type of disease that targets a wide variety of plants. Most commonly, it affects nightshades (eggplants, tomatoes, peppers), cucurbits (melons, cucumbers, pumpkins, squash), and legumes (peas, beans).

Once the fungus begins to take over any of your plants, a layer of mildew spores will form over the surface of its leaves. The wind will then carry these spores towards the other plants, thus infecting them.

Powdery mildew may slow down plant growth. In severe cases, it can even reduce fruit quality and yield.

Powdery mildew spores thrive in dry, warm climates but require a relatively high humidity level. In wet, cool temperatures, the mold spores tend to spread slower and only affect plants in shady areas without direct exposure to the sun.

For more information about this fungus, read this article on how long do powdery mildew spores live.


How to identify powdery mildew?

There are visible signs of powdery mildew you should watch out for.

  • Infected plants look like they were dusted with flour.
  • Circular, powdery white spots that appear on stems, leaves, and sometimes on fruits are an early sign of powdery mildew.
  • Visible mildew spores are usually found on the upper part of the leaves but can sometimes also grow on the undersides.
  • Leaves infected with powdery mildew turn yellow and dry out.
  • Powdery mildew may cause the leaves of the affected plant to break, disfigure, or twist.
  • The white spores will spread throughout the leaves and eventually cover most of the surface or affected area.
  • The buds and growing tips of the infected plants may disfigure as well. Such symptoms happen in the late part of mildew growth. 


Treating Powdery Mildew On Japanese Maples

Once powdery mildew infects your Japanese maples, it may be hard to get rid of it, so as much as possible, do everything to prevent it from happening in the first place. 

However, you can still do some remedies to deal with the disease.


1. Baking soda

Baking soda has proven its power over different types of mildew, including powdery mildew. To use this, just mix one teaspoon of baking soda with 1 quart of water. 

Spray the solution in the affected Japanese maples. It will eliminate the fungus that it comes into contact with.


2. Milk

It may sound a bit odd, but milk is also an effective remedy to treat powdery mildew. Dilute milk with water in a typical ratio of 1:10.

Spray it on the maples which are in the early stage of infection. The solution can also be used as a preventive measure- not bad, right?


3. Organic fungicides

Organic fungicides that include sulfur, neem oil, lime-sulfur, and potassium bicarbonate are effective in treating powdery mildew. They work wonders, especially when used in the early stages of infection or preventive measures.

If you are also interested in other mildew treatments on plants, learn from this article on how to clean grow room after powdery mildew.


Preventing powdery mildew

There is no better way to combat powdery mildew than to be proactive. Here are some preventive measures you can follow.

  • Avoid putting plants that are prone to a fungal infection near your Japanese maples. Choose those that are mildew-resistant.
  • Plant your Japanese maples in areas where there is direct sunlight. Powdery mildew has a higher chance of developing in shady areas.
  • Prune or trim your Japanese maples regularly to promote good air circulation, which will lessen humidity, thus a lower chance of fungal infection.
  • When watering, do it from overhead to help wash the spores off the leaves. 
  • Once a part of the maple is infected, remove it immediately to avoid spreading and destroy them by either burning or tossing them into the trash can.
  • Never compost any infected plant as it is possible that the spores may get carried by the wind and spread the disease to other plants.



Plants, just like humans, also get infected by diseases, and powdery mildew is the most prominent culprit. The same saying goes for them, too, that prevention will always be better than cure.

If not plant enthusiasts, people tend to neglect plants thinking that they are fine just with water, sunlight, and fertilizer. However, it is absolutely not true as they also require proper and regular maintenance.

Japanese maples are a very pleasant type of maple tree. As much as they are a feast to the eyes, they can also be a feast to fungi like powdery mildew.

It is a good thing that the question “how do you treat powdery mildew on Japanese maples?” has been answered. You can now continue blessing your eyes with the beauty nature offers.

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