Main content area

Control of blue mold of apples by preharvest application of Candida sake grown in media with different water activity

Teixido, N., Vinas, I., Usall, J., Magan, N.
Phytopathology 1998 v.88 no.9 pp. 960-964
apples, Malus domestica, Candida, Penicillium expansum, water activity, biological control, biological control agents, acclimation, population dynamics, storage, harvest date, field experimentation, cold storage, fungal antagonists, application timing, postharvest diseases, Spain
Unmodified and low water activity (a(w))-tolerant cells of Candida sake CPA-1 applied before harvest were compared for ability to control blue mold of apples ('Golden Delicious') caused by Penicillium expansum under commercial storage conditions. The population dynamics of strain CPA-1 on apples were studied in the orchard and during storage following application of 3 x 10(6) CFU/ml of each treatment 2 days prior to harvest. In the field, the population size of the unmodified treatment remained relatively unchanged, while the population size of the-a(w)-modified CPA-1 cells increased. During cold storage, the populations in both treatments increased from 10(3) to 10(5) CFU/g of apple after 30 days, and then declined to about 2.5 x 10(4) CFU/g of apple. In laboratory studies, the low-a(w)-tolerant cells provided significantly better disease control as compared with the unmodified cells and reduced the number of infected wounds and lesion size by 75 and 90%, respectively, as compared with the nontreated controls. After 4 months in cold storage, both unmodified and low-a(w)-tolerant cells of C. sake were equally effective against P. expansum on apple (>50% reduction in size of infected wounds).