Improved Postharvest Disease Control of Penicillium digitatum on Citrus Fruits by Combined Application of Compatible Biocontrol Agents

摘要

Pseudomonas spp. and Trichoderma spp. strains were tested in vitro and in vivo for their antagonistic properties against Penicillium digitatum, the causal agent of green mould of citrus. Several bacterial and fungal strains strongly inhibited the growth of the pathogen in vitro assays. Inhibition of P. digitatum growth was increased when Pseudomonas and Trichoderma strains were combined, showing synergic efficacy of the mixtures. Incidence of citrus decay was consistently reduced in vivo when strains were applied in wounds 24 h and 72 h before challenging P. digitatum. Even in "in vivo" biocontrol assays, the mixtures of bacterial and fungal biocontrol agents were more effective than either agent used alone. These experiments clearly indicate that Pseudomonas spp. and Trichoderma spp. strains could be considered as biocontrol agents for citrus green mould and support the hypothesis that a more effective disease control is given by the combined action of the two agents.