Anthracnose of plane: what the agencies record
What Forest Research, the Royal Horticultural Society and Colorado State University Extension say about anthracnose of plane and sycamore: the fungus, the susceptible species, the bud, shoot, leaf and twig stages by season, the frost-damage look-alike and the weather that favours it.
Checked against the sources at the bottom of this page on October 8, 2026. Rules, fees and pay change: the source has the last word.
This page reports what the official source says. It is not legal advice: ask the office named here. It lists what the sources record about plane anthracnose and does not diagnose any tree. The list of other diseases is on the tree diseases page. A neighbouring plane disease with a notifiable status is on the canker stain of plane page.
At a glance
| Item | What the sources say |
|---|---|
| Pathogen | Apiognomonia veneta, an ascomycete fungus. Forest Research calls it a foliar disease, one that affects leaves, twigs and buds. |
| Hosts | Plane trees (Platanus). Forest Research says western plane (American sycamore) is highly susceptible, oriental plane is fairly tolerant, and London plane varies with the clone. Colorado State Extension says it can also infect ash, elm and maple. |
| Where | Forest Research says it is common and widespread in the United Kingdom, continental Europe, the USA, Russia and New Zealand. |
| Status in the United Kingdom | Present and not notifiable. Forest Research says it is not necessary to report suspected cases, because most planes are managed by organisations with regular inspections by trained tree-care professionals. |
How the sources say it spreads and what it does
Forest Research says the fungus overwinters in fallen leaves and one-year-old twigs and releases spores from fruit bodies just as buds begin to flush, and that spores landing on emerging leaves cause the shoot and leaf blight later in spring. The Royal Horticultural Society says the spores are rain-splashed from tiny fruiting bodies on affected twigs and leaves. Forest Research says the long-term effect on an individual tree is usually relatively minor, though badly affected trees can lose many leaves. The Royal Horticultural Society says affected trees usually recover.
Symptoms by season as the sources state them
- Winter. Forest Research and the Royal Horticultural Society both say twig and bud blight develop during warm spells while the tree is dormant, when the fungus keeps growing and kills bark.
- Spring. Forest Research says the fungus girdles the vascular tissue leading to buds, which causes bud blight, and that twigs encircled by the fungus die back. It says shoot blight comes later in spring and early summer, after the leaves emerge.
- Leaves. Forest Research describes brown staining along the veins and brown, crinkled patches on mostly green leaves. Colorado State Extension describes rapid wilting of new leaves, a brown lesion along the main veins of older leaves, and curling and falling leaves.
- Twigs and branches. Colorado State Extension says cankers often form at the base of blighted leaf clusters, can girdle and kill larger branches, and that repeated yearly twig death leaves clusters called witches' brooms.
- Summer. Forest Research says the fungus goes dormant in twigs and branches in summer, and that new shoots and leaves at that time often stay free of symptoms, especially in hot, dry summers. It says even severely affected trees usually make new growth by mid-summer.
Weather and look-alikes
Forest Research and the Royal Horticultural Society say shoot blight usually follows cold spring weather that slows shoot growth, and that leaf blight is favoured by a warm and wet spring. Forest Research adds that the disease tends to be more common in years with prolonged, mild, wet springs. Colorado State Extension says an average temperature below 55 degrees F in the two weeks after first leaves open means serious shoot blight, and that little or none occurs above 60 degrees F. All three sources say the early damage can be confused with frost damage. Forest Research says frost damage shows no canker on the twigs and no staining of the wood below damaged buds. Colorado State Extension also says the natural fuzz on a sycamore leaf is not infection. The sources read describe no laboratory test. Forest Research names three other plane problems: massaria, elbow-patch crust disease and the usually fatal canker stain of plane.
What the agencies publish for control
Forest Research lists non-chemical cultural methods: raking and burning fallen leaves where practical, pruning out affected twigs or branches on young, small trees, thinning the crown to improve air flow, selecting London plane cultivars believed to tolerate the disease, and cleaning tools, clothes and vehicles between trees. It says chemical treatment is not generally recommended for this disease in the United Kingdom, although it is sometimes used in other countries. The Royal Horticultural Society says no fungicides are available to gardeners for it. Colorado State Extension lists fungicide options and says injections into large trees are done by licensed pesticide applicators. Who may apply pesticides is covered on the pesticide licences page.
Credit
The Forest Research material was read under the Open Government Licence v3.0 and is restated here in our own words.