Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: March 20, 2003
Publication Date: August 1, 2003
Citation: Janisiewicz, W.J., Peterson, D.L. 2003. Susceptibility of the stem pull area of mechanically harvested apples to blue mold decay and its control with a biocontrol agent. Phytopathology 93:S40. Technical Abstract: Labor shortages in the U.S. necessitate development of a mechanical approach to harvest apples. A new harvester which uses a rapid displacement actuator on main scaffolds to remove apples from trees with narrow-inclined trellises has shown good potential. With this technique, loss of stem during harvesting ranges from 20 to 57%, depending on cultivar. If a portion of apple skin is removed together with the stem, flesh tissue is exposed creating a potential point of entry for pathogens. We evaluated the susceptibility of the stem area, with and without stem pulls, to blue mold decay on 11 cultivars of mechanically harvested apples, and the effectiveness of P. syringae (used in BioSave 110) to control these decays. On fruits with stem pulls inoculated with P. expansum decay incidence ranged from 0% on 'Jonagold', 'Pink Lady', and 'Suncrest' to 41% on 'Empire'. On other cultivars it ranged from 1.7 to 8.3%. On fruit with the stems, decay did not exceed 3.3%, except on 'Gala' (6.6%). P. syringae reduced decay on fruit with stem pull to 3.3% on 'Empire' and 'Gala', and below that on other cultivars with seven cultivars having no decay.