• The London plane tree, Platanus x acerifolia, is a cross between an American sycamore tree and an Oriental sycamore. This hybrid tree is used in cities because it grows well in a variety of soils and is easy to transplant. It does need well-drained soils, but will still thrive in soils that are not perfect. Another benefit of the plane tree is that it tends to resist most pests and diseases, though it is susceptible to several diseases such as anthracnose, canker stain and powdery mildew.
  
  

Anthracnose

• Anthracnose are fungal diseases that affect many species of shade trees, including the plane tree. The disease is also know as leaf or twig blight because of the damage it causes to the leaves and branches, leaving depressed areas where the fungi grow and eventually kill the leaf or section of branch. Anthracnose is caused by several different fungi, including Stegophora ulmea, Glomerella species, Apiognomonia errabunda, Apiognomonia veneta and Colletotrichum gloeosporioides. These fungi cannot survive and spread when the climate is dry and need rain or irrigation water to reproduce. Once infected, a plane tree will drop its leaves too soon and will sometimes lose all of its leaves. This disease does not infect mature trees as much as younger ones that have not developed resistance.
  
  

Canker Stain

• The fungi Ascomycete and Ceratocystis fimbriata cause the disease called canker stain. This disease spreads and kills plane trees quickly. The cankers are the distinguishing sign that a plane tree is infected. Cankers are dark purple--almost black--oval-shaped and long, and show up on the branches in the crown of the tree. The fungus infects the tree and destroys the inner parts of the trunk, causing wilt and death. Canker stain is spread by different insects that pick up the spores due to their stickiness. In addition to being spread by insects, people and trimming equipment can carry the spores from tree to tree. Therefore, all equipment, including gloves, boots or clothing worn by trimmers, should be thoroughly disinfected in a bleach solution to kill any spores that have adhered.
  
  

Powdery mildew

• Powdery mildew (Microsphaeria penicillata) is a fungal disease that infects the plane tree, primarily the Bloodgood plane tree. An infection of powdery mildew is fairly easy to detect as it leaves exhibit a tell-tale white powdery substance created by the spores. On the plane tree, powdery mildew will infect and destroy flowers, leaves and newly emerging buds. Leaves will fall prematurely. The fungi will only infect live trees and cannot grow on dead branches or leaves. Powdery mildew spores are carried by wind and, unlike canker stain, the spores do not need water to survive. The spores like a warm climate, but will likely die off during high heat of 95 degrees and above. A fungicidal spray can be used on infected and non-infected trees to control the disease, but planting trees in full sun will also help.