Or if the spots are more free-form, that could be anthracnose, another common leaf disease. “My Japanese maple looks really sick and not as full as usual. Some are small, about fifteen to twenty feet in height while some grow to seventy feet or more in height. I've read that there is no treatment for this condition. You can see several small spots on the leaves and cankers on the branches. Avoid getting water directly on tree leaves (by overhead irrigation) because fungi thrive in wet conditions. Tar spot is not a serious problem and so no treatment is recommended. These diseases are usually more severe on red, sugar, and silver maple but can occur on Japanese and Norway maple. Anthracnose is scientifically recognized as Colletotrichum spp. The disease mostly shows up in April and May. The honeydew excreted by sucking insects provides them the required nourishment. Request a free consultation today to get to the bottom of your Japanese maple tree problems. Tar spots on the maple leaves develop as a small yellow spot and turn black afterwards. The fungus has the power to cause serious damage to the sugar maple. For some trees, leaf spot and anthracnose can mean a few dots on leaves here and there. Get in touch with us and we'll talk... Any tree can be a victim of sooty mold disease but this disease is most commonly seen on boxelder, elm, linden, and maple. As the fungus grows within the leaf, these areas develop into distinctive, slightly raised, shiny, tar-like, black spots on the leaves. on Nov 4, 2017. The trees are more likely to suffer from the disease, in the prolonged cold and moist weather. Control the Infestation…, Treatment for Orange Balls on Cedar & Juniper Trees (Rust Fungus). Answer . Nectria cinnabarina canker This maple tree disease can be identified by its pink and black cankers on the bark and typically affects parts of the trunk that were weak or dead. These cookies do not store any personal information. Copyright © Gardenerdy & Buzzle.com, Inc.