Colored canker is a disease that affects the plane trees along the Canal du Midi. It probably was introduced into France via infected wooden ammunition crates imported from the United States. It is caused by a microscopic fungus (Ceratocystis Fimbriata ssp. Platani) that attacks exclusively plane trees. It penetrates the heart of the wood, then blocks the sap channels and kills it in 2 to 5 years. It is, however, a disease that is harmless to humans and animals.