Trident maple issues help

Hi all

So I am in the uk and have three trident maples, different age and size and also kept apart by at least 10 meters, but they all have this leaf issue this spring - now I have treated before leaf out with fungicide and just as they leafed out but all have this black marking on the leafs and in most areas of the tree , one of them has cured up slightly with black ends and the other two just the marks. I have watered them when dry and think the watering should be ok - two were repoted this year and one last year but all have the issue. I really hope some experience person could nail the issue and not just the (could be over/under water or fungus problem) I expect one of those but hoping someone will know with certainty which. Thanks all

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Well sadly it’s the two things you didn’t want to be suggested. It is indeed fungus and it is there because the trees have been too wet (overwatered) or it is because its been in a cool wet environment (common spring weather). It looks to me to be anthracnose.

What you can do about it:

  1. tilt one side of the pot to facilitate better drainage
  2. let dry out a little more between waterings
  3. do not water the foliage
  4. start with application of antifungal sprays. I like the following sprays, vinegar/water, hydrogen peroxide/water, neem oil, copper fungicide
  5. use systemic fungicides
  6. do all of the above

Sorry mate, my maples (JMs, TMs, Acer skuttchi) all have been affected as well this spring. It happens, had a mild, warm, wet winter and spring. I kept my trees outdoors with no protection from rain and had to treat them. I’ve cleared the infection and now the foliage is growing healthy. Good luck with your trees, I hope you get the infection under control.

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Thanks for the reply it’s annoying as I have watered not much at all and very free drainage mix, but can’t shift it with rose clear or anything you can buy here, I don’t know of anything you can buy in uk with copper but will try the rest of the ingredients you suggest


Not sure if these are available where you are live, Clearys 3336f and Daconil Fungicide might be good options.