Project Overview
A Young Scholar Enhancement Grant was awarded for this project in 2025.
Information Products
Commodities
- Fruits: peaches
Practices
- Crop Production: crop improvement and selection
- Pest Management: integrated pest management
Abstract:
The Southeastern U.S. is the second-largest peach-producing region in the country. However, producing peaches in the southeast is challenging due to the climate favorable for pest and disease development. In addition, orchard soils have low soil organic carbon content, meager soil fertility, and poor soil structure, which inflicts tree stress that negatively impacts pest and disease tolerance and may lead to reduced yields. Current commercial practices do little to improve the soils.
Bacterial diseases intensify from both the favorable climate and stress-induced predisposition to infection. Bacterial spot (caused by Xanthomonas arboricola pv. pruni) and bacterial canker (caused by Pseudomonas syringae pv. syringae) are the two most important bacterial diseases of peach and cause significant direct annual losses - up to $22 million in South Carolina and Georgia alone (estimates from SC/GA Peach Councils). Bacterial spots on peach leaves could lead to severe defoliation, and spots on fruit significantly reduce the marketable yield. Bacterial canker on woody tissues leads to shoot death and tree death. Managing these two diseases is very challenging. There are no cultivars with absolute resistance to either of the two diseases; only a few cultivars are tolerant to bacterial spot and no cultivar has tolerance to bacterial canker. Currently, no chemical control options are available for bacterial canker, and bacterial spot management mainly relies on weekly sprays of copper and antibiotics during the growing season. These chemicals could negatively impact the environment and have led to emergence of copper-tolerant and antibiotic-resistant pathogens, as recently found in SC, indicating an even greater need for new management options.
Our goal was to improve sustainability of the southeastern peach production systems by developing holistic strategies to improve disease management and tree health. In collaboration with peach producers, a multi-disciplinary team of plant pathologists, horticulturist, soil biogeochemist, economist, and entomologist conducted systems research to: 1) develop sustainable tree spray programs with biopesticides to reduce bacterial diseases; 2) assess sustainable soil management practices and their integration with spray programs on reducing bacterial diseases; 3) evaluate the spray programs and soil practices and their integration on tree health/performance, soil health, and management of other diseases and pests; and 4) develop an enterprise budget for organic peach production. In this project, we identified the best biopesticide spray program in both dormant and growing seasons that consistently reduced spring canker and bacterial spot on both leaves and fruit without causing phytotoxicity. We found that addition of organic materials could enhance soil ecosystem function, reduce tree nutritional stress, improve tree health, activate tree self-defense, improve water retention and nutrient cycling, thereby reducing bacterial disease pressure and improving fruit marketable quality. The first enterprise budget for organic peach production in South Carolina was developed. We conducted outreach activities to disseminate project results to producers, agricultural professionals, the scientific communities, and general public. We expect our findings to benefit the entire production system of peach as well as other stone fruits affected by the same diseases, and to contribute to the long-range improvement of U.S. agriculture.
Project objectives:
- Develop sustainable spray programs with biopesticides to reduce bacterial diseases;
- Assess sustainable soil management practices and their integration with spray programs on reducing bacterial diseases in research orchards;
- Evaluate the independent spray programs and soil practices and their integration on tree health/performance, soil health, and management of other diseases and pests;
- Develop an enterprise budget for organic peach production.