Canker and anthracnose are general terms for a large number of different plant diseases, characterised by broadly similar symptoms including the appearance of small areas of dead tissue, which grow slowly, often over a period of years. Some are of only minor consequence, but others are ultimately lethal, and of major economic importance in agriculture and horticulture. Different cankers and anthracnoses are caused by a wide range of organisms, including fungi, bacteria, mycoplasmas and viruses. The majority of canker-causing organisms are tied obligately to a single host species or genus, but a few will attack a wider range of plants. Canker can be spread by weather and animals, making an area that even has a slight amount of canker hazardous.
Some cankers are treatable with fungicides or bactericides, but many are not; often the only treatment available is to destroy the infected plant to prevent the disease from spreading to other plants.