Novel film-forming formulations of the biocontrol agent Candida sake CPA-1: biocontrol efficacy and performance at field conditions in organic wine grapes.

Abstract

The biocontrol agent (BCA) Candida sake CPA-1 has previously effectively reduced Botrytis bunch rot (BBR) and it was also suggested as a promising strategy to control sour rot in grapes under field conditions. However, biocontrol efficacy of solid formulations of CPA-1 has never been tested in field trials. The present study aims to confirm the efficacy against BBR and sour rot in grapes under field conditions of two novel formulations recently developed by the addition of biodegradable coatings using a fluidized-bed spray-drying system. Novel film-forming formulations of the BCA C. sake CPA-1 controlled B. cinerea as well as liquid formulation. Sour rot control resulted better in the second season and severity reductions were more satisfactory than incidence control. Visual and cryoSEM observations revealed that film-forming treatments were uniformly distributed on plant surfaces. CPA-1 coating could be observed on grapes at harvest time. The results of this work suggest that solid formulations would be a competitive alternative to conventional fungicides because they were easy to package and transport, and cell viability could be maintained for a long period of time. © 2018 Society of Chemical Industry.