Pseudomonas syringae strains ESC-10 and ESC-11 survive in wounds on citrus and control green and blue molds of citrus

Two Pseudomonas syringae strains (ESC-10 and ESC-11) controlled green and blue molds of citrus caused by Penicillium digitatum and Penicillium italicum, respectively, on both lemons and oranges. The efficacy of disease control by strain ESC-10 was superior to that of strain ESC-11. Application of strain ESC-10 reduced the incidence of green mold 31.1% more than application of strain ESC-11. Bio-Save 10, an EPA-registered product of EcoScience Corp. containing strain ESC-10 as its active ingredient, reduced the incidence of green and blue mold by 87.9% on lemons and by 58.6% on oranges compared to water-treated controls. Population sizes of both strains remained similar over 2 weeks in wounds on lemons. Population sizes of ESC-10 decreased within 1 week on the surface of lemons, whereas in wounds, the infection court of the green and blue mold fungi, the populations decreased more slowly. Population sizes of strain ESC-10 in wounds on lemons or oranges did not differ. Population dynamics of these bacteria were not predictive of their differential efficacy as biological control agents. (C) 1997 Academic Press