Black spots on tree leaves are one of the more common calls Bear Creek receives during summer, and the cause isn't always the same. Several different fungal diseases, insect infestations, and environmental conditions can produce dark spotting or discoloration on leaves, and the treatment, or whether treatment is even warranted, depends on correctly identifying which one you're dealing with.
Apple scab affects ornamental crabapples and apples, producing dark, velvety spots that can lead to significant early leaf drop by mid-summer. Septoria leaf spot and anthracnose affect a wider range of tree species and tend to appear after wet spring periods. Aphid honeydew, which isn't a disease but a secretion, creates a sticky residue that supports sooty mold growth, leaving dark patches on leaves and stems beneath affected branches.
In many cases, a single season of spotting doesn't warrant chemical treatment, particularly in otherwise healthy trees. Repeated infections over multiple seasons, or spotting combined with other symptoms like dieback or thinning canopy, are stronger indicators that an arborist should take a closer look. Bear Creek's ISA Certified Arborists can assess leaf symptoms and give you an honest evaluation of whether treatment is needed and what it involves.
We serve Englewood, Denver, Lakewood, Littleton, Centennial, and Aurora. Free estimates available.
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A close-up of leaf spotting or discoloration on an affected tree, or an arborist examining leaves on a job site. Real diagnostic photo strongly preferred over stock imagery.
Canva text suggestion: "Black Spots on Leaves? Let an Arborist Take a Look." or "Leaf Disease ID: Know Before You Treat"