Hello,
I acquired this elm from a greenhouse late last summer. It had about ten leaves when I got it. It responded well. I wintered it in non-heated greenhouse. We had a really mild winter so I treated everything with mancozeb in early spring.
Unfortunately, these black spots are taking over but I don’t think it’s Anthracnose.
Any ideas? Do I need to prune all infected leaves?
Thank you.
Can you rub the black spots off? If so, can you get a look at them with a magnifying glass. Actually looks like a type of scale, but hard to say from the pic without a closer look. If that’s the case I’d say remove infected leaves then treat.
Ewww! Sorry, but I’m no help with that. Should probably still remove the leaves that are affected to try to at least slow the spread. Hopefully someone who has seen that before will chime in. The closeup pic will probably help. Good luck.
Thanks for the advice. I pruned all infected leaves. We’ll see what happens.
Update. I defoliated the tree, treated it with Malathion (since I had already treated with Mancozeb in the Spring), and put it my recovery area in dappled light under the maples. The poor tree had about 5 leaves left. But…
Thanks for your advice.
Yea! Love a happy ending!
Lookin good! How does the tree look now, almost a year later? Did you ever figure out what the black spots were?
Bryan
Thanks for checking in. I never found out what the black spots were but so far they have not returned. Made sure to have good percolation by cleaning off the top soil that had developed over the fall and winter. Watching water and oxygen. I am adding beneficial nematodes to the water cycle as well.
If they return I’ll let you know. Fingers crossed.
That is a fungus called black spot. It will infect your elm tree every year about this time, after the first flush of new leaves. I have a 50+ year old U. Parvifolia that has the disease. The problem with the fungus is that is that it doesn’t kill your tree quickly, but weakens it over time. It is caused when you mist the leaves or keep the tree in an overly humid environment. The solution is to:
Thanks for the info. I will take caution not to allow the leaves to get wet.
Thank you for the great advice. I have a CE given to me by my neighbor that had just a handful of leaves on it. Now it’s growing quite well but some of the new leaves have those black spots. With your help, I now have a plan to help it thrive. I live in the Pacific NW and plan to keep the tree outdoors so it will go dormant and then I can proceed. And your beautiful tree is an inspiration!
I followed your advice this spring (March). Bare rooted, planted it in new soil, and now am applying Neem every 4 weeks. The tree is much happier–thanks again for your guidance and inspiration!
When I bare rooted the tree, I discovered hardly any roots and part of the trunk was missing below the surface. It looked like it was sliced or ripped off when it was originally planted as a commercial plant. (Sorry, I forgot to take a picture.) I’m letting the tree grow this year and next before doing any major design work. I’ll do a little clip and grow if it needs it but I hope to get the roots back into shape in the next couple years.
Audree
Edmonds, WA
Looking good Audree! Based on your narrative, it looks like the tree was probably the result of an air layer that was separated from its trunk too soon. Inadequate roots resulted in inadequate foliage which weakened the tree and made it susceptible to black spot. So killing off the fungus during dormancy and replacing the infected soil, was a good first step. Now, continue with fertilization (Higher P), watering and aeration practices that will maximize root growth, and you will be able to start shaping the tree.
Thank you! Great tip about the higher P when fertilizing.
Audree
Sorry to resurrect this old thread, but I’m dealing with what looks like this exact issue now with a cork bark Chinese elm I repotted exactly 1 month ago.
The tree recovered quickly after repotting and blew up shortly after with healthy leaves, and it’s seemed happy in its new pot. About 2 weeks ago though I noticed one branch had some leaves that were dropping, it almost looked like they were being nibbled, but I couldn’t see anything wrong with them. I wondered if maybe that one branch’s fresh green foliage got scorched as it was facing the afternoon sun, so I just kind of watched it. Unfortunately, the tree has started to get rapidly worse and the problem is spreading to new branches. I’m now seeing a subtle difference in the color green throughout the foliage, and there are a handful of leaves that have these characteristic black spots on them. I thought it was scale at first too, but got out a good magnifier and even tore up a leaf with a toothpick, and the color does seem to be within the tissue of the leaf. Concerned for a fungal problem, I I treated a few days ago with Mancozeb for a few days in a row (I added a granular systemic insecticide to the soil surface too for good measure). I’m just trying to baby it now, ensuring it gets appropriate water/drainage and plenty of sunlight. I think maybe the problem has slowed, it doesn’t seem to be shedding leaves as quickly, but the leaf discoloration is still present and I’m not seeing a ton of new growth. I’m hesitant to do a full defoliation now while the tree is weak, but I’ll remove spotted leaves as I see them and plan to hit it with Clearys 336 as a next step unless others here have better ideas.
@Makuen-amer do you have any sense for how contagious this is to other trees on my bench? It is an opportunistic infection that attacked a weakened, freshly repotted tree? Or is everything in my collection now at risk?
Oops! Systemics on chinese elms is not always a good idea. They will frequently cause your elm to drop its leaves, and sometimes will weaken the tree so it dies. So check the label and make sure it’s approved for use on elms. It’s hard to tell without pictures, but I would likely withhold the insecticide for now, cut back on the water (without leaves it won’t need as much) and wait for it to put out new foliage. Keep removing the infected leaves. Then follow the process described above. Others on the Forum may have a different approach.
If it is a funal disease, it can spread to nearby plants. Dutch elm disease spreads through the roots. Other fungi can be airborne. Daconil, which is not a sustemic, is frequently recommended. Before using any fungicide, it’s crucial to carefully read and follow the instructions on the product label. Additionally, it’s a good idea to test the fungicide on a small area of the tree first to ensure that it doesn’t cause any adverse reactions. If you’re unsure about which fungicide to use or how to apply it safely, consider consulting with an experienced bonsai artist or horticulturist for guidance tailored to your specific situation.
Water/oxygen balance the key. Paid closer attention and the elm spot went away over a couple of seasons. I kept it away from my other trees just in case.
