Control of citrus green mold with Aspire is impacted by the type of injury

Aspire, a formulation of the yeast Candida oleophila registered for postharvest application to citrus for the control of green mold (Penicillium digitatum), competes with the pathogen for nutrients at injuries to prevent infection. A major factor affecting efficacy is how quickly and well the yeast colonizes injuries to the fruit surface, including minor injuries involving only oil vesicles. Colonization of puncture-related injuries that either encompassed oil glands or individually ruptured glands was achieved within 1-2 days at 21 degrees C. Colonization of puncture injuries by C. oleophila was comparable after 2 days at 21 and 30 degrees C, but no colonization occurred at 13 degrees C. Ruptured oil glands were colonized more effectively if treated 7 h after injury rather than immediately. Peel oil was toxic to cells of C. oleophila but not to spores of P. digitatum. Candida oleophila colonized punctures more uniformly than individually damaged oil glands, and provided more effective control of green mold originating at punctures than at oil gland injuries. Incubating treated fruit at 30 degrees C for 2 days before storage at 21 degrees C enhanced the control of green mold, and control was significantly improved by the addition of Aspire in one of two trials. (C) 2000 Elsevier Science B.V. All rights reserved.