White spots on Japanese maple are ones that you would worry about, but you should know that they must be treated as soon as you spot them. These can severely stunt your growth in the current season, and this could mean a lot for your specimen tree.

White Spots on Japanese Maple

To get rid of the cause, you ought to know what it is, and aim to tackle them. We’re here to help you find out what’s going on and how to treat your maple back to health.

What Causes of White Spots on Japanese Maple?

The causes of white spots on Japanese maple are powdery mildew, leaf spots, and blight. In addition, it could also be the result of scale insects. These would inhibit the plant and cause it to develop little dots of white color.

– Powdery Mildew

If you’re seeing spots on your Japanese maple, your number one thought should be mildew, and that is the exact problem that will attack this plant. This is a fungal disease that’s the most spread in the plant world and Japanese maples are no exception. Being a fungi-caused disease, this one will thrive in humid and hot conditions, and it would develop and cause chaos.

This one emerges when heaps of fungal spores are found in one place where they stay dormant. Often they come to leaves via air and water and there they stay until perfect conditions are met. This is when they begin to germinate and develop, as they came from another tree that had been contaminated.

This disease is easy to identify, and it is because those spots are easily disturbed, which means they are in a superficial condition. They are easily smudged across the surface just by running your finger through them. What is actually good though, is that this disease won’t do any substantial damage to your tree.

– Leaf Spots and Blight

Spots and blight are diseases commonly caused by several other species of fungi. What makes them different from mildews is that these will damage and bite your leaves! This will come in a range of colors, often white in the center and then black or brown as they spread and grow bigger.

White Spots on Japanese Maple Reasons

Maple leaf spot fungi thrive in moist conditions and are easily spread via water droplets and stale weather conditions. In humid climates, this disease is often taken without any worry, because it usually goes away on its own as soon as the sky clears, and more air circulation is introduced; in short, the atmosphere would clear the air.

– Scale Insects

If your spots are looking like they’re crawling then you aren’t dealing with diseases, likely this is a pest infestation. This type of maple tree will often be fighting against mealybugs and aphids, both sap-sucking insects that will do a lot of damage if left on your tree unchecked. They would harm the tree in the long run, and the white spots would become much more in their number.

The microscopic beings often cluster together to protect themselves and begin eating your leaves by sucking the life out of them. These insects will poop honeydew onto lower leaves and soil, which can cause the formation of diseases such as sooty mold.

Methods of Fighting White Spots On Japanese Maple

The methods of fighting white spots on Japanese maple are pruning the infected areas, spraying some fungicides, and also placing chemical-free pesticides on the leaves that have white-colored circles. By using these ways, you will fight the issues and keep the plant healthy.

– Pruning

Powdery mildew isn’t harmful, but if you cannot stand the look of it you can take some action. Maple will react well from partial or complete defoliation of its infected foliage, so you’re free to cut and remove any infected leaves. By doing so, you are getting rid of the damages that were on your tree, and they will no longer contaminate the rest of the leaves.

– Spray Fungicides

Another way to tackle this would be to use a general fungicide or a homemade mixture of rubbing alcohol and soapy water and spray the rest of the canopy and branches. This solution will help your maple fight any remaining and future fungal spores.

After a week or two, you should see your maple bursting into life with new green and fresh-looking foliage, with no more white-colored dots on top of them. If you want to prevent fungal and bacterial diseases from happening, always use clean tools and apply fungicides now and then during the growing season.

This way, the tree will thrive when the right season comes, and it will have good health, where pests will not infest.

– Place Some Chemical-free Pesticides

Magnolia scale, mealybugs, and aphids are a nuisance that can lead to all sorts of problems and can even cause further diseases. When dealing with insects, pesticides are quite effective. However, too strong chemicals can unnecessarily destroy the tissue of your leaves. That’s why we propose you use a more subtle mixture.

Methods of Fighting White Spots on Japanese Maple

And this one is made out of neem oil or any other horticultural oil. What you should do is mix a full tablespoon of these with a gallon of water and spray generously over an entire tree.

The leaves will benefit from being soaked every once in a while, and those compounds will suffocate any insects that the liquid finds on its way. After this, you can scrub the bark and the leaves with some rubbing alcohol solution to make sure no insects are left alive.

If you’ve been dealing with an infection that went too far, then you may see some sooty mold either on the bark or the container where you’re growing your maple. In short, here’s how to deal with it; you will soon see that no issue has been left because these oils have tackled them problem.

As this isn’t a tree disease, but a superficial disease of the sap, there’s not much you can do, except clean it off. Just mix some rubbing alcohol or hand-washing soap with water and rub the spots clean. That way you got rid of both white dots and the black spots caused by fungi.

Apply Fertilizers to Remove White Spots


Those Japanese maples are wonderful specimen plants and their leaves are beautiful things of joy, growing in abundance on every tiny branch. What can go wrong is when those leaves turn white, so let’s go through what we’ve said in this article:

  • If your maple develops white smudges, you should always study the tree to determine what exactly caused those white things.
  • If the issue was mildew, and you reacted like you’re dealing with insect infestation, you’re probably going to do more harm than good.
  • To prevent diseases from occurring on your maples, you should always apply fertilizers, and fungicides and allow for awesome air circulation, especially in the growing period.

Japanese maple or Acer Palmatum is an increasingly popular maple tree specimen. These are grown as amazing bonsai trees as well as garden giants. And now that you know how to handle that white stuff on your maples, your trees will be so much happier and that much more productive.

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