Summary: The objectives of this project were: 1. Determine the sources and availability of inoculum of Sphaeropsis pyriputrescens in the orchard during apple-growing season. 2. Determine seasonal susceptibility of apple trees to infection by S. pyriputrescens in the orchard. 3. Determine susceptibility of apple fruit at different growth stages to infection by S. pyriputrescens in the orchard in relation to Sphaeropsis rot during storage. 4. Test sensitivity of the fungus to various fungicides including new postharvest fungicides. 5. Determine the prevalence and incidence of Sphaeropsis rot as well as other postharvest diseases on major apple varieties under various handling systems. 6. Evaluate effectiveness of preharvest fungicides and postharvest drench with fungicides in controlling Sphaeropsis rot.
