Bacteriophage As a Promising Biocontrol Agent for Pectobacterium Carotovorum, Inciting Potato Soft Rot Disease

caused by Pcc. The results show that up to 90% and 100% of potato tubers inoculated with four Pcc isolates show distinctive soft rot with , 0.9x10 4, 0.3x10 4 and 0.6x10 3 PFU/g for Pcc 1, Pcc 2, Pcc 3 and Pcc 4, respectively, but the longevity of formulated phages not affected by storage more than three weeks with a concentration of 4x10 10 , 2x10 9 , 5x10 7 and 2x10 7 for Pcc 1, Pcc 2, Pcc 3 and Pcc 4, respectively. It was found that 10 7 and 10 9 PFU/ml compared to the initial concentrations did not decrease the efficacy of disease control. Potato yield increased with phage treatment up to 70% when all tubers were inoculated with Pcc isolates. The current findings corroborate those of Balogh (2002), who produced three formulations to increase the lifespan of bacteriophages on plant foliage for the management of tomato bacterial spots. These formulations were (i) PCF (0.5% pregelatinized corn flour (PCPF + 0.5% sucrose), (ii) Casecrete (0.5% Casecrete NH-400, a water-soluble casein protein polymer + 0.5% sucrose + 0.25% PCPF 400)), and (iii) skim milk (0.75% powdered skim milk + 0.5% sucrose). In comparison to non-formulated phage populations, these formulations resulted in a 4,700, 38,500, and 100,000-fold increase in phage populations two days after application. In field testing on tomato, the PCF, Casecrete, and skim milk formulations, as well as the non-formulated phages, all reduced disease severity by 22, 33, 27 and 19 percent, respectively, when compared to the usual copper-mancozeb therapy. In three field studies, the PCF and Casecrete formulations reduced disease severity by 11 and 21%, respectively, when compared to the non-formulated phage. relative the non-formulated