Plane anthracnose is more commonly known as sycamore anthracnose. The disease affects plane and sycamore trees, which are species of the Platanus family, but it is more common on sycamore trees.
Anthracnose refers to a group of fungal diseases that affect numerous plant species. Each type of fungus attacks specific host plants. Members of the Platanus family, including plane and sycamore trees, are susceptible to the Gnomonia fungus, which causes plane anthracnose.
Plane anthracnose overwinters in cankers on affected trees. In the spring, it produces spores, which are spread by the wind and rain. The best temperature for optimal growth of the fungus is between 50 and 55 degrees. The disease is worse in wet springs.
The symptoms of plane anthracnose appear in early spring. Twig blight is caused by cankers that girdle and kill small twigs. The leaves are affected by shoot and leaf blight. First the leaves become crinkly and brown, similar to frost damage. Next dead brown areas form along the veins of the leaves. As the spots spread, the leaves drop off the tree.
In severe cases of plane anthracnose, cankers can form on larger limbs and the tree may lose all its leaves. Repeated defoliation can weaken the tree, causing it to be more susceptible to insects and other diseases.
Plane and sycamore trees should be planted where they receive good air circulation. Diseased twigs, limbs and branches should be pruned and destroyed. Debris should be removed from around the tree and destroyed.
A fungicidal spray for anthracnose on plane and sycamore trees can be used according to the manufacturer's directions. For adequate control, it should be applied in the spring before signs of the disease appear.
A trained arborist can inject a systemic fungicide into the trunk of affected trees in September to control the disease.
London plane trees are more resistant to plane anthracnose than the American sycamore. Some varieties of London plane trees are more resistant than others, such as "Bloodgood," "Columbia," and "Liberty." Oriental plane trees are the most resistant to the disease.