Cornell Scientists Identify Fungal Pathogen Causing Bitter Rot in Apples

Researchers at Cornell University have identified the fungal pathogen that causes bitter rot in apples. This fungus is in the genus Colletotrichum, as is a related fungus that causes rot on other fruit, which this study found for the first time on apples. Growers in New York suffer bitter rot losses as high as 25% per year, and organic growers have experienced crop loss to bitter rot. Identifying the pathogen responsible for bitter rot will help growers understand the environmental conditions that produce the disease, and they can look for ways to manage those conditions. In addition, scientists can begin work on breeding resistant apple varieties. The study’s senior author commented, “We think that the range of these pathogens is expanding because of global warming, however, more work needs to be done to demonstrate this.”