plane anthracnose

Symptoms

Brown angular leaf lesions following veins, twig dieback + cankers on young shoots, premature defoliation of entire trees in epidemic years, witches' broom symptoms in chronic infections, characteristic black fruiting bodies on dead twigs in winter.

Easily confused with

• Plane powdery mildew

  How to tell them apart: Erysiphe platani (plane powdery mildew) forms a white to grey powdery coating that sits ON the leaf surface and wipes off, with young leaves curled, pale and stunted. Apiognomonia veneta (plane anthracnose) instead causes brown to tan necrotic blotches that follow the leaf veins, plus bud death, shoot dieback and twig cankers, with no powdery growth that wipes off; anthracnose damage is darkest in cool, wet spring weather, whereas the mildew is favoured by warm, dry conditions with high humidity.