If you looked at your maple in August and thought something was badly wrong, you were not imagining it and you were not alone. Across Monroe County and the Finger Lakes, Norway maples turned brown and shed their leaves well ahead of schedule this year, skipping fall color entirely. Enough homeowners noticed that state foresters and Cornell Cooperative Extension educators spent late summer answering the same question.
The short version is reassuring. This is a leaf disease having a very good year, not a new threat to your tree.
What is happening to Rochester's maples this year?
The culprit is tar spot, a fungal leaf disease caused by Rhytisma acerinum and its relatives. It shows up first as small raised black spots on green leaves, glossy and slightly domed, looking rather like someone flicked tar across the foliage. Heavily spotted leaves brown at the edges, curl, and fall early.
Tim Wenskus, the Finger Lakes regional forester for the New York State Department of Environmental Conservation, described the 2026 situation plainly: "We've had an awful lot of tar spot this year because it was really wet in the spring, which made the perfect conditions for the spores of this fungus to spread around."
The reporting that brought this to public attention centered on a western Irondequoit neighborhood, which is to say inside Monroe County rather than somewhere distant. Norway maple is the species taking the worst of it, which matters locally because Norway maple was planted heavily as a street and yard tree across Rochester's older neighborhoods for decades. Silver and red maples also pick it up, generally less severely.
Our guide to black spots on maple leaves in Rochester covers how to identify tar spot up close and how to tell it apart from the diseases that genuinely threaten a tree.
Why was tar spot so severe in 2026?
Tar spot overwinters in fallen leaves. In spring, the fungus produces spores that travel on wind and splashing rain to the new leaves emerging above. That handoff needs moisture, and it needs the timing to line up with leaf-out.
A wet spring gives the fungus exactly that. Spores stay viable longer, rain splash moves them further, and young leaves stay wet long enough for infection to take. One damp spring in Upstate New York can turn a disease that is normally a background nuisance into something visible on every maple down the street.
That is why the severity swings so hard year to year while the underlying fungus stays the same. It is a weather story more than a tree health story.
Field note · When to call a pro
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Get a Free Estimate →Will my maple survive this?
Almost certainly yes. DEC's position is that tar spot is not fatal to a healthy tree. What it costs your maple is the tail end of one growing season and this year's fall color.
The reason it is survivable comes down to timing. By the time tar spot has built up enough to force leaves off, in August and September, the tree has already banked most of the sugar it needed from the season. Losing leaves in late August is a very different event from losing them in June. Barring another problem underneath, an affected maple should leaf out normally next spring.
The trees worth worrying about are the ones that were already struggling. A mature maple dealing with girdling roots, construction damage, compacted soil, or several consecutive drought years has less in reserve, and repeated early defoliation is one more withdrawal from an account that is already low. If your tree has been thinning from the top for several seasons, tar spot is a symptom of a bad year rather than the explanation, and sugar maple decline in Upstate New York describes that slower pattern.
What should I do with the fallen leaves?
This is the one action that genuinely changes next year, and it costs nothing but an afternoon.
Because the fungus overwinters in leaf litter directly beneath the tree, leaving the leaves in place stocks the infection for next spring. Wenskus put the distance in memorable terms: "If the leaves are just sitting underneath your tree all winter long, then come springtime, the fungus only has 10 feet to go to get back into your tree again."
So rake them up and get them off site, or compost them somewhere hot and far from the tree. Mulching them into the lawn where they fell does not help. This will not eliminate tar spot, since spores travel from neighboring properties and from any Norway maple within range, but it removes the reservoir sitting directly under your own canopy.
Fungicide is generally not worth it for tar spot on a mature shade tree. Treatment has to go on early in spring, before symptoms are visible, and it protects appearance rather than tree health on a disease that does not kill trees. On a large maple the coverage problem alone makes it impractical.
What else makes a Rochester tree drop leaves early?
Tar spot is the 2026 headline, but early leaf drop has several ordinary causes worth ruling in or out before you settle on an answer.
- Drought stress. A tree sheds leaves to cut its water losses. Leaves usually yellow briefly, then fall, often from the interior outward. Newly planted trees are far more vulnerable here, which is why a proper watering schedule for a young tree matters so much in the first three seasons.
- Anthracnose. Another wet-spring fungal leaf disease, more common on sycamore, ash, oak, and maple. It browns leaves in irregular blotches that follow the veins rather than forming discrete round spots. Our guide to anthracnose on Rochester shade trees covers the difference. On oaks specifically, margin browning with a yellow halo that returns worse each August points instead at bacterial leaf scorch.
- Normal shedding. Trees routinely drop their oldest, most shaded interior leaves in late summer. A light scatter is not a symptom.
- Root and trunk problems. Girdling roots, deep planting, and soil compaction all restrict water movement, and early leaf drop is often the first visible sign.
The pattern of browning tells you more than the fact of browning. Distinct raised black spots point to tar spot. Blotchy browning along the veins points to anthracnose. Edge browning across whole leaves usually points to water. Our guide to curling, yellowing and dying leaves walks through the distinctions.
Field note · When to call a pro
Want a certified arborist to take a look?
Monster Tree Service of Rochester offers free estimates and a full plant health care program across the Rochester area.
Get a Free Estimate →When is early leaf drop actually serious?
Some patterns deserve a professional look rather than a rake.
Watch for branches dying one at a time while the rest of the canopy looks fine, which is the signature of verticillium wilt in maples, a soil-borne vascular disease that is genuinely serious and is often mistaken for a bad leaf year. Watch for a whole canopy wilting and bronzing rapidly over a few weeks, which in oaks raises the question of oak wilt. Slow margin browning on an oak that worsens every August is a different problem, bacterial leaf scorch. Watch for repeat defoliation across three or more consecutive years, for mushrooms at the base of the trunk, and for bark that is cracking or peeling on the main stem.
Any of those moves the question from "is this year unusual" to "is this tree failing," and the two need different answers. Our diagnostic guide to a sick tree is the place to start narrowing it down.
FAQ
Is tar spot going to kill my maple?
No. New York State DEC states that tar spot is not fatal to a healthy tree. It costs the tree the last few weeks of one growing season and this year's fall color. A maple that is otherwise sound should leaf out normally the following spring.
Why were Rochester maples so much worse in 2026 than other years?
An unusually wet spring. Tar spot spreads by spores moving from last year's fallen leaves to newly emerging foliage, and that transfer needs moisture. DEC's Finger Lakes regional forester Tim Wenskus attributed the 2026 severity directly to wet spring conditions creating ideal circumstances for spore spread.
Should I rake up the leaves or leave them?
Rake them up and remove them from the area. The fungus overwinters in the leaf litter beneath the tree, so leaving it in place keeps the infection source about ten feet from next spring's new leaves. This will not eliminate tar spot, because spores also arrive from neighboring maples, but it removes the reservoir under your own canopy.
Is this the same thing as verticillium wilt?
No, and the difference matters. Tar spot is a leaf disease that produces distinct raised black spots and is cosmetic. Verticillium wilt is a soil-borne vascular disease that typically kills branches one at a time while the rest of the canopy looks healthy, and it is genuinely serious. If your maple is losing whole limbs rather than just leaves, that needs a professional diagnosis.
Do I need to spray my maple next spring?
Usually not. Fungicide for tar spot has to be applied at bud break, before any symptoms are visible, and it protects appearance rather than the tree's health on a disease that does not kill trees. On a mature shade tree, achieving full coverage is impractical anyway. Leaf removal is the more sensible control.
