Spots on Japanese Male tree - Ask Extension
Hi,
I planted a Japanese Maple in my backyard last fall. Looks good but I have some rust or yellowish spots on the leaves. Just noticed in the p...
Knowledgebase
Spots on Japanese Male tree #871790
Asked June 05, 2024, 6:04 PM EDT
Hi,
I planted a Japanese Maple in my backyard last fall. Looks good but I have some rust or yellowish spots on the leaves. Just noticed in the past week. Any idea?
See photos.
Wayne County Michigan
Expert Response
Good Morning,
The damage appears to be purple bordered leaf spot- Phyllosticta. Purple Bordered Leaf Spot – Wisconsin Horticulture
Although purple-bordered leaf spot may look unsightly, the disease is usually only a cosmetic problem, rarely causing significant damage to mature and vigorously-growing trees. Occasionally, the disease may defoliate trees early in the growing season, but these trees are typically able to produce new leaves within a few weeks. Defoliated trees should be watered (about one inch of water per week), and properly fertilized (based on a soil nutrient test).
You may also email pictures to MSU Plant and Pest Diagnostic laboratory for a second opinion. Include a picture of the whole tree from soil line to top of canopy. Include details like how you water the trees ( sprinkler or soaker hose?), how much water, and which chemicals or fertilizers have been used within 12- 15 feet of the plants, or on the plants themselves, and when they were last used.
The email consultation is free of charge. If the lab needs to analyze leaf samples there is a fee for that. Their website describes how to submit samples, the fee schedule, and has the lab contact information. https://www.canr.msu.edu/pestid/
I hope this helps. Thanks for using our service.
The damage appears to be purple bordered leaf spot- Phyllosticta. Purple Bordered Leaf Spot – Wisconsin Horticulture
Although purple-bordered leaf spot may look unsightly, the disease is usually only a cosmetic problem, rarely causing significant damage to mature and vigorously-growing trees. Occasionally, the disease may defoliate trees early in the growing season, but these trees are typically able to produce new leaves within a few weeks. Defoliated trees should be watered (about one inch of water per week), and properly fertilized (based on a soil nutrient test).
You may also email pictures to MSU Plant and Pest Diagnostic laboratory for a second opinion. Include a picture of the whole tree from soil line to top of canopy. Include details like how you water the trees ( sprinkler or soaker hose?), how much water, and which chemicals or fertilizers have been used within 12- 15 feet of the plants, or on the plants themselves, and when they were last used.
The email consultation is free of charge. If the lab needs to analyze leaf samples there is a fee for that. Their website describes how to submit samples, the fee schedule, and has the lab contact information. https://www.canr.msu.edu/pestid/
I hope this helps. Thanks for using our service.
