Identifying Diseases that Limit Pomegranate Production in Georgia

Summary

To provide a basis for developing disease management tactics in support of the fledgling pomegranate industry in Georgia, a plant disease survey was initiated to characterize the fruit disease complex on pomegranate and to identify cultivars or selections with resistance to the most common pathogen species in the southeastern production environment.

Situation

Owing to the well-publicized health benefits associated with its high content of beneficial antioxidants, consumption of pomegranate juice has increased considerably in the United States and other industrialized countries. A recently published Feasibility Study by the University of Georgia's Center for Agribusiness and Economic Development has indicated that a juicing facility for pomegranate in southeastern Georgia could provide an excellent return on investment, potentially providing new opportunities for income and diversification in this economically impoverished area. However, the study also acknowledged that there are numerous unknowns regarding the horticultural performance of pomegranate, a fruit crop native to Persia, in Georgia's challenging production environment. Knowledge gaps are especially acute with respect to the incidence and importance of plant diseases in limiting yield and quality of pomegranate in the Southeast.

Response

Fruit disease surveys were conducted in a pomegranate test planting near Ty Ty, GA, during the time of harvest (third week of September) in 2009. Symptomatic fruit (exhibiting spots, blotches, rots, fruit mummification, russeting, and/or cracking) were obtained from 21 different cultivars or selections and assessed microscopically and by culture plating for the presence of plant-pathogenic fungi. Cercospora fruit spot (caused by the fungus Cercospora punicae) and russeting (primarily an abiotic disorder) were found to be most common, occurring on more than 75% of symptomatic fruit. Cracking (45.4% incidence) and blotching (29.2% incidence) also occurred commonly on symptomatic fruit, but the causal agent(s) could not be identified unequivocally to date. More than one-third of the symptomatic fruit had at least two different disease symptom types present. None of the cultivars and selections evaluated showed resistance to all diseases and disorders included in this survey.

Impact

Our study revealed that the disease complex on pomegranate in Georgia is diverse and different from that in other production areas such as California or the Mediterranean, where Alternaria, Aspergillus, and Botrytis diseases dominate. Whereas some symptom types were limited to certain cultivars, more than 90% of cultivars and selections grown at the test site appeared susceptible to Cercospora fruit spot, indicating that supplemental disease management tactics will need to be developed for this disease. The development of a viable pomegranate industry in Georgia will require active and vigilant disease management on the side of the producers.

State Issue

Agricultural Profitability and Sustainability

Details

• Year: 2010
• Geographic Scope: State
• County: Tift
• Program Areas:
  • Agriculture & Natural Resources