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What To Do About Powdery Mildew On Japanese Maples

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Powdery mildew is a common fungal disease that can affect Japanese maples. This disease can cause the leaves of the tree to turn yellow, brown and become covered in a white, powder-like layer. To prevent and treat this disease, please follow the recommendations below.

First, it is essential to maintain your Japanese maple tree’s health by making sure it receives enough water, sunlight, and fertilizer. Keeping an eye on the soil moisture levels and making sure the tree is not too wet or too dry is also important. Pruning and removing dead or diseased branches on a regular basis can also help reduce the risk of powdery mildew.

Second, it is important to keep your Japanese maple tree free of debris and other objects that can harbor moisture. This will help to reduce the chances of powdery mildew developing. Furthermore, regularly cleaning the area around your Japanese maple tree can also reduce the risk of disease.

Third, you can also use fungicides and other treatments to help prevent and treat powdery mildew. These treatments can be applied in the early spring or late fall, and should be reapplied after rainfall or when the humidity levels are high. Always follow the directions on the label and wear gloves and a face mask when applying any treatments.

Finally, it is important to monitor your Japanese maple tree for any signs of powdery mildew. If you notice any white, powder-like layers on the leaves, you will need to take action immediately. It is best to consult with a qualified arborist for the best course of action. By following these recommendations, you can help prevent and treat powdery mildew on your Japanese maple tree. Maintaining the tree’s health, removing debris, and using fungicides can all help to reduce the chances of the disease affecting your tree.
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Patrick ONeill - July 21, 2023

My fine leaf japanese maple has a severe case of powdery mildew. What brand of fungicide do you recommend? Also, how long do fine leaf japanese maples live (I have a small one in my front yard that is about 17 years old that seems stressed, it also has fungus-like growths on its branches)

Sandy - July 21, 2023

I recently had my roof cleaned of lichen that had collected. I think that some of what was used on the roof dripped onto my dwarf Japanese Maple – now half of it has shriveled up but the branches are still green. On one of the branches, a white dust has appeared as well – but that could be from what was used on the roof because the lichen also turns white. I really want to save this bush – is there anything I can do?
Thank you!

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