90 



ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 46 



Fig. 89. — For the prevention of anthracnose, sycamores should be 

 sprayed when the buds are swelling and the bud caps are beginning to break. 



Anthracnose causes insufficient injury of London plane trees 

 to justify spraying for control. Control of anthracnose of oak is 

 described in the section on oak. 



Canker Stain. — Canker stain, caused by the fungus Cerato- 

 cijstis fimbi'iata f. platani, is a deadly stem disease of London 

 plane trees. Known principally in the eastern and southeastern 

 parts of the United States, it has been reported in Missouri but 

 not in Illinois. However, it could easily spread into the East St. 

 Louis area from St. Louis, Missouri, where it was found in 1947. 



This disease has been reported on sycamore, which appears 

 to be much less susceptible than London plane. It may affect 

 either branches or trunks of trees. On London plane trees, it 

 produces dark brown or black cankers on smooth bark. On old 

 rough bark, diseased areas appear first as elongate depressions or 

 furrows. Beneath these areas the inner bark is blackened and 

 dead. The diseased areas continue to enlarge in succeeding years. 

 The wood beneath the diseased bark is stained reddish brown or 

 bluish black. The discoloration is most conspicuous in the wood 



