Japan Maple leaf spots

ABCarve

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A friend has these spots on all her maples. Anyone know what it is?
 

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ABCarve

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Not that I know of. She said it showed up after a rain.
 

lordy

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It's on some of my maples too. One has it every year. Didnt matter if in a pot or in the ground. I believe it to be a fungus of some sort, although I seem to associate fungi with damp conditions. I might call my climate humid, but not really damp, but that might be splitting hairs.
I dont believe the story of water drops on the leaves and the sun turns them into a magnifying glass. Too many times that simply does not happen for me to believe it.
 

RKatzin

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I find that the red Japanese Maples, Atropurpureum in particular have a tendency to water spotting, whether from the sun or not, they just don't seem to like getting wet in the heat of the day. Mornings or late afternoon seems to suit them better, as far as getting the leaves a nice shower. Rick
 

0soyoung

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I would guess that it is Phyllosticta leaf spot or a similar fungus.

Leafs don't get burned because of water spots acting as little lenses. There might be an association by the droplets picking up and harboring fungal spores, I suppose.
 

Jalcon

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Probably water droplet burn. JM'S are very prone, a few of mine have that as well.
 

ABCarve

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So, is this anything serious? Is it worth using a fungicide? Or, just a cosmetic inconvenience?
 

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jk_lewis

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It is a rust. Remove the leaves and destroy them.
 

GrimLore

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Looks like a Fungus to me called Anthracnose and it can be treated with a Fungicide. Usually the result of a damp Spring. If it is get rid of the infected leaves, burning is best and treat.

Grimmy
 

CubanBonsai

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Japanese Red Maple leaf tip burn.

I don's have the exact same problem but one of my Japanese Maples have small burned leaf tips. They are pre-bonsai trees, and I keep them in a clay pot on a balcony. Here in northeast Ohio it rains at least once a week, temperatures in the day can go up to the 90s and at night it may drop to 65. (USDA Hardiness Zone 5a)

Are burned leaf tips a common issue for Japanese Red maples? If not, what can I do to help my small trees.

Thank you
 

Stan Kengai

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I don's have the exact same problem but one of my Japanese Maples have small burned leaf tips. They are pre-bonsai trees, and I keep them in a clay pot on a balcony. Here in northeast Ohio it rains at least once a week, temperatures in the day can go up to the 90s and at night it may drop to 65. (USDA Hardiness Zone 5a)

Are burned leaf tips a common issue for Japanese Red maples? If not, what can I do to help my small trees.

Thank you

Burning/wilting of leaf margins, where no insect damage is evident, is usually a sign of root problems. Most likely, you're keeping you plant too wet.

BTW, you would probably get more attention if you started your own thread about your problem. But this particularly problem has been rehashed many times here.
 
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I believe that sun burning through water droplets has long been determined to be a myth.

The spots are a fungus. Start spraying once a week with Mancozeb when buds start swelling. and it will not appear on your tree.

Alternately get the Bayer tree and shrub systemic fungicide and follow the directions. Without going and getting the jug it says something like spray every two weeks till you have applied it four or six times and you are done spraying for the year.

Either method will do away with the fungus till next year when you need to do it again. If your tree already has the spots and you just want to stop it from getting worse then spray it.

If you defoliate completely and start another crop of leaves then start applying right after defoliation to the branches and trunk. I put a plastic sheet over the soil so it doesn't run into the soil and kill any beneficial fungus camping there.

Same stuff is good for cedar/apple rust, pine funguss and what ever fungus attacks azalea leaves.
 
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