Improved postharvest disease control of Penicillium digitatum on citrus fruits by combined application of compatible biocontrol agents.
Penebianco S, Scuderi G, Scala F, Lorito M, Vinale F and Cirvilleri G
Program and Abstracts, 11th International Citrus Congress (ISC Congress), 26-20 October 2008, Wuhan, China. 333 pages.
2008
บทคัดย่อ
Ten Pseudomonas spp. and five Trichoderma spp. strains were tested in vitro and in vivo for their antagonistic properties against P. digitatum, the causal agent of green mould of citrus. Several bacterial and fungal strains, but not their culture filtrates, strongly inhibited the growth of the pathogen in vitro assays on different substrates. Spore germination in PDB was also greatly controlled by Pseudomonas spp. cell suspensions as well as by culture filtrates. Inhibition of P. digitatumgrowth was increased when Pseudomonas and Trichoderma strains were combined, showing synergic efficacy of the mixtures. Inhibitory effects of fungal growth and conidial germination were synergically increased by mixing Trichodermaculture filtrates and Pseudomonas cells. Combination of bacterial and fungal culture filtrates generated only an additive response, indicating that the presence of living bacterial cells was required for a synergistic effect. Incidence and severity of citrus decay in vivo were consistently reduced 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. The development of decay was more effectively inhibited in small-scale dip-treatments, whereas the efficacy of the mixtures was not significantly different in either the dip treatments or in the wound inoculation. These experiments clearly indicate that Pseudomonas spp. and Trichoderma spp. strains could be considered interesting biocontrol agents for citrus green mould, supporting the concept that a more effective disease control is given by the combined action of the two agents.