The symptoms of black spot on a Chinese Elm Bonsai

We have just received this enquiry from Dave Barden on our Facebook Page and thought readers may find it helpful in identifying early stages of black spot on Chinese Elms. Please click on this link if you would like to see the conversation: http://www.facebook.com/BonsaiDirect?sk=messages_inbox&action=read&tid=id.100919306728855

Hi there,
Hope you don't mind me mailing you, I have a Chinese elm about 8 yrs old, been growing well, pruned nicely etc, this past week / fortnight alot of its leaves are going yellow and dropping off, can you tell me why or give me any advice please. this is quite new to me ive had the tree about 4 months and its been ok up until now.
Thanks
Dave.

Dave has also sent us some photos.

  • Hi Dave, thanks for the photos. I believe this is one of 2 things.
    It is most likely to be the early stages of black spot ( a fungus). The spores are in the air and Chinese Elms are susceptible. It is easily treated, you can buy a fungicide which treats for black spot and spray ASAP and again a week later. I would then use it once a month as a preventive measure. We spray weekly as a precautionary measure.
    The only other thing it could be is red spider mite (but I cannot see any signs of very fine webbing or leaves which are hanging off the branches).
    Both black spot and red spider mite show the mottling of the leaves as in your photos in the early stages; this is why I am slightly unsure.
    I hope this helps,
    all the best
    Sarah

2 thoughts on “The symptoms of black spot on a Chinese Elm Bonsai”

  • Bonsai Direct

    Dave did check for signs of webbing on his bonsai to ascertain if the symptoms are more likely to be red spider mite or black spot. There was no indication of Red Spider Mite & the mottling on the leaves is very even so it is most likely to be Black Spot, so treatment with a fungicide should solve the problem.
    If a bonsai does get red spider mite you cannot see them. You need to look for symptoms because they are too small to see with the naked eye. Mottling of leaves and leaves hanging by a thread. Also very fine webbing!

    Reply
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