Use of biocontrol agents in combination with physical and chemical treatments: efficacy assessment

Abstract

Purpose of review: This review discusses the combination of biological control agents with physical (heat, gamma or UV-C irradiation, controlled atmosphere) or chemical (salt additives, chitosan, natural plant products) treatments against the main postharvest fruit diseases. Findings: The use of biocontrol agents (BCAs) to control postharvest fruit diseases is still constrained by the lack of high levels of disease control required in the postharvest phase (more than 95%). Their inconsistent activity is one of the main factors preventing their routine application on fruit after harvest. Therefore, to overcome this issue, integrated strategies were explored and continue to be one of the fields most investigated in postharvest fruit disease control, in order to achieve maximum effectiveness. The combination of BCAs with physical and chemical treatments, including fungicides at low doses, resulted in an increase of BCAs effectiveness against fungal diseases such as Pencillium spp., Monilinia spp., Botrytis cinerea , etc. Since the integration of different treatments could benefit from their additive or synergic effects and improve the efficacy of each single method. Limitations: It is unrealistic to assume that BCAs have the same fungicidal activity as pesticides; the evaluation of their compatibility with other methods therefore seems to be the main topic that will be developed in the near future. Nevertheless, it is necessary to evaluate the possible detrimental effects of some treatments like gamma irradiation or essential oils on qualitative fruit parameters in view of their commercial application. In addition, the use of low doses of fungicides cannot be applied to organic production. Directions for further research: Specific appropriate strategies have to be evaluated for each species and pathogen in order to tailor a complete integrated disease management. Moreover, these integrated applications have to be investigated at commercial levels, including during fruit handling, in order to ascertain their practical efficacy.