Help identifying spots on tree leaves - Ask Extension
The picture submitted is a leaf from a 12' tall autumn blaze (I think) maple tree in Grand Haven. At present there are perhaps a dozen leaves which ...
Knowledgebase
Help identifying spots on tree leaves #870399
Asked May 28, 2024, 11:43 AM EDT
The picture submitted is a leaf from a 12' tall autumn blaze (I think) maple tree in Grand Haven. At present there are perhaps a dozen leaves which have the 'spots' now appearing as holes in the leaf with a brown ring around the missing material. This one has the color other than brown, & the top side is like braille in the center of the approximately 3/8" discolored area & the bottom side is correspondingly indented.
Are you able to tell me what sort of insect or egg might be present & the severity of the infestation & if you would recommend some form of treatment
THANK YOU>
Ottawa County Michigan
Expert Response
Good Morning,
Symptoms of Phyllosticta leaf spot on many maple species include the development of small (approximately 1/5 inch), roughly circular, brown spots with dark reddish or purplish borders. Japanese maples develop yellowish or tan spots, which sometimes have transparent centers. A circular pattern of black fungal fruiting bodies may be seen in the dead areas on infected leaves. On some maples, the diseased center portions of the leaf spots may fall out, giving a shothole appearance to the leaves. Infection occurs on wet leaves by water-splashed spores. Wet weather in spring and early summer favors disease development. The fungus probably overwinters on fallen leaves or on buds and twigs of host trees. This disease is not considered a serious landscape problem.
To get a firm diagnosis you can submit pictures to MSU Extension’s Plant and Pest Diagnostic Lab at: https://www.canr.msu.edu/pestid/
A certified arborist would be able to assess your tree also. To find an arborist in your area, go to www.treesaregood.org,
Maple: Phyllosticta leaf spot | Hortsense | Washington State University (wsu.edu)
I hope this helps. Thanks for using our service.
Symptoms of Phyllosticta leaf spot on many maple species include the development of small (approximately 1/5 inch), roughly circular, brown spots with dark reddish or purplish borders. Japanese maples develop yellowish or tan spots, which sometimes have transparent centers. A circular pattern of black fungal fruiting bodies may be seen in the dead areas on infected leaves. On some maples, the diseased center portions of the leaf spots may fall out, giving a shothole appearance to the leaves. Infection occurs on wet leaves by water-splashed spores. Wet weather in spring and early summer favors disease development. The fungus probably overwinters on fallen leaves or on buds and twigs of host trees. This disease is not considered a serious landscape problem.
To get a firm diagnosis you can submit pictures to MSU Extension’s Plant and Pest Diagnostic Lab at: https://www.canr.msu.edu/pestid/
A certified arborist would be able to assess your tree also. To find an arborist in your area, go to www.treesaregood.org,
Maple: Phyllosticta leaf spot | Hortsense | Washington State University (wsu.edu)
I hope this helps. Thanks for using our service.
