Could preharvest applications of Pantoea agglomerans CPA-2 control the main postharvest diseases on citrus fruit?
Rosario Torres, Inmaculada Viñas, Teresa P. Cañamas, Josep Usall and Neus Teixidó
Abstracts Book, 6th International Postharvest symposium, 8-12 April 2009, Antalya, Turkey. 256 pages.
2009
บทคัดย่อ
Postharvest green mould, caused by Penicillium digitatum is one of the most economically important postharvest diseases of citrus in all production areas characterized by low summer rainfall. This disease often occurs in the field prior to harvest. Therefore, it could be advantageous to apply biocontrol agents before harvest, which would reduce initial infection and then remain active and control pathogens in storage and/or commercial conditions. However, biological control at field conditions is usually limited by fluctuating environment and by the narrow range of environmental conditions. The main goal of this research was to determinate the practical influence of different formulation strategies on the survival and efficacy of Pantoea agglomerans CPA-2 cells under field conditions, including lyophilized cells, osmotic adaptation of P. agglomerans by NaCl treatments and additives. Different additives, such as summer oils, alginate, glycerol and food additives were tested mixed with P. agglomerans in laboratory studies. The additive that provided the highest bacterial viability on oranges was the food film Fungicover (FC) at 50 g/l. In general, osmotic adapted and lyophilized P. agglomerans cells showed greater survival rates than non-osmotic adapted or fresh cells when these bacterial treatments were sprayed in field conditions. However, this superiority was only found when additive Fungicover was also added to suspension treatments. These results allowed us to conclude that it is possible to improve environmental stress tolerance and ecological competence of P. agglomerans cells by integrating certain formulation strategies, and it is feasible to control postharvest diseases by preharvest treatments.