LEXINGTON, Ky. — While fruit rots have a variety of causes, the most common fungal fruit rot of apple in Kentucky is bitter rot. The disease results in rotten, inedible fruit. Fungicides are available for management; however, sanitation is critical for disease prevention. Ongoing research at the University of Kentucky is providing new insights and understanding of the pathogens that cause bitter rot.
Bitter Rot Facts
- Symptoms begin as small, slightly sunken lesions that enlarge and eventually develop a bull’s-eye pattern (Figure 1). Cutting into infected fruit reveals an internal rot with a V-shaped pattern (Figure 2).
- Symptoms may not appear immediately after infection and may take several months to develop.
- Initial infection begins as early as bloom and may continue through harvest.
- The fungal pathogen overwinters in fallen fruit, dried fruit (mummies), and in crevices in bark and dead wood.
- Bitter rot is caused by multiple species of the fungus Colletotrichum.