Black spot problems, please advise

dragonshade1

Hi everyone, I am new to bonsai, and will be getting a couple to begn my new hobby. My problem is this - Around my home (suburbs of Atlanta, GA) I have 3 Red maple trees. The trees are about 20 years old and good size. Every summer the leaves get black spots on them. This never defoliates the trees at all, but eventually the black spots become small holes. You wouldn't really notice this until you looked closely at the leaves. After talking to some tree people I have heard that this is a fungus, and supposedly in maples, esp. red maples, this is very common. Now there are many trees I mean A LOT all around the house/property so I am sure if this is true there are huge amounts of spores everywhere, in other words...impossible to get rid of. The maples are doing great though, otherwise healthy and between 30-45' tall now (after 20 years). Over the last couple years I have planted some Oaks, and Japanese Maples. This year I saw the black spots on both my Nutall Oak, and Red Oak that I planted, but not on the Japanese Maples, or my Live oak. The location cannot be a factor. My concern is if I get my bonsais that they will also contract this, as their best location would be under the largest of these effected Red Maples, but even if I pick another spot the spores would still be everywhere. I do not know what to do. I really don't see any way to treat with a fungicide of anykind, because there are so many trees around, and I cannot feasibly treat the entire neighborhood. Any ideas would be great.
Thanks

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ALDEVAUX

There are differrent types leaf spots on maple caused by different fungi pathogens. By the symptoms you describe, it may be tar spot caused by Rhystima sp. or Phyllostica leaf spot. To be completely sure you need to compare closely the symptoms of your leaves with those on the references I am given you below. However, if other species of trees have the same spots, it will not be tar spot which is specific to maples. You may need to get a proper identification from you local agriculture extension service.

The best way to control the spots on your potted trees is to move them
in the dryest possible places and out of the rain and mists because the fungus needs lost of moisture to infect the leaves.

Fungicide treatment as recommended in your area may be needed if you cannot control the environment but are much easier to apply, and thus more effective, on small potted trees than big grounded trees where the sprays do not easily cover all parts of the leaves.

http://www.extension.umn.edu/projec...cnosemaple.html
http://www.gov.on.ca/OMAFRA/english...4/26hrt04a6.htm
http://plantclinic.cornell.edu/Fact...ot/tarspots.htm

Best of luck.

dragonshade1

Thanks so much for the links. Though I am perplexed....from reading them it has got to be the tar spots. The timing of and description of symptoms is right on. Though I know I saw what looked to be the same spots on the Northern Red oak I planted a year ago for sure. The oak is near one the maples and was SEVERELY stressed this past year (approx. 6 months after planting). It had a wonderful horizontal branch about 1/2 way up the tree (tree is about 8'), and some lovely neighbor, or neighborhood child ripped it clean off the tree leaving a bad wound into the heartwood of the trunk. It is healing, but shortly after this happened I noticed the spots on it's leaves. Wonder if it is a different fungus that was just opportunistic. Thanks again