title: Survival of the biological control agent Candida sake CPA-1 on grapes under the influence of abiotic factors.
abstract: OBJECTIVE
  As reliability of preharvest applications of biological control agents (BCAs) to control fruit pathogens is highly dependent on the survival of the selected organism, this study aimed to describe the population dynamics of the yeast-BCA Candida sake (Saito & Ota) CPA-1 on grape berries under the effect of abiotic factors such as temperature, relative humidity, sunlight and rainfall.
  
  
  RESULTS
  Candida sake (5 × 10(7) CFU ml(-1)), combined with different concentrations of the food additive Fungicover(®), was applied on grape berry clusters. Treated clusters were then exposed to abiotic factors in field or laboratory conditions, recovering populations to describe C. sake population dynamics. The addition of Fungicover significantly increased C. sake multiplication under optimal growth conditions and improved survival under fluctuating abiotic factors. After field applications, significant differences in populations on grape bunches exposed or covered by fine foliage were detected. Simulated rainfall washed off C. sake populations by 0·6-0·9 log units after 20 mm of rain volume. Allowing populations to establish for 24 h or more, prior to a rain event, persistence on grape berries significantly increased and the effect of rain intensity was not observable.
  
  
  CONCLUSIONS
  Candida sake demonstrated high survival ability under unfavourable environmental conditions and persistence under intense rain. The study evidenced the importance of the first period just after application for C. sake survival on grape tissues and also the protective effect of the additive Fungicover.
  
  
  CONCLUSIONS
  This research provides new information on the survival of C. sake under field conditions and its practical implications for recommending timing of spray with this antagonist. Our results could be useful for other yeast antagonists applied before harvest. This work, for the first time, defines population dynamics of a yeast BCA using simulated rainfall.
authors.affiliation: Food Technology Department, XaRTA-Postharvest, Agrotecnio Center, University of Lleida, Lleida, Catalonia, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Calvo-Garrido
authors.forename: I
authors.initials: I
authors.lastname: Viñas
authors.forename: J
authors.initials: J
authors.lastname: Usall
authors.forename: M
authors.initials: M
authors.lastname: Rodríguez-Romera
authors.forename: M C
authors.initials: MC
authors.lastname: Ramos
authors.forename: N
authors.initials: N
authors.lastname: Teixidó
mesh_terms: D061046:Biological Control Agents; D002175:Candida / Q000502:physiology*; D005503:Food Additives; D005638:Fruit / Q000382:microbiology; D050296:Microbial Viability; D011891:Rain; D027843:Vitis / Q000382:microbiology*
chemical_list: D061046:Biological Control Agents; D005503:Food Additives
keywords: Vitis vinifera; extreme conditions; fatty acids; rainfall; sunlight; vineyard