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Phytopathogenic bacteria affect a wide variety of crops, causing significant economic losses. Natural biocides are the alternative to chemical methods of phytopathogens control. The goal of the present study is the evaluation of the biocidal activity of the following: 1) the extract of orange wax (EOW); 2) zinc ferrite nanoparticles (ZF-NPs); 3) the EOW adsorbed on the ZF-NPs; and 4) the EOW/ZF-NPs washed with 40% ethanol. For the biocidal activity, three phytopathogenic bacteria were used, namely, Xanthomonas axonopodis pv. Vesicatoria (Xav) Erwinia amylovora (Ew), and Pseudomonas syringae pv. Phaseolicola (Psph). For the ZF-NPs, an inhibitory effect higher than 50% (${p} < \textsf {0.05}$) was observed for Xav respect to the antibiotic used as positive control. On the other hand, the ZF-NPs did not show inhibitory effects on both Ew and Psph. In addition, the EOW in dimethyl sulfoxide (DMSO) at 100% caused growth inhibition on Xav, bacteriostatic activity on Ew, and had not biological activity on Psph. To the best of our knowledge, the control of Xav by zinc ferrites and orange wax, and the bacteriostatic effect produced by orange wax extract on Ew have not been reported elsewhere. Orange wax and zinc ferrite nanoparticles show potential in control of phytopathogenic bacteria. However, the bactericidal effect depends on the bacterium, the concentration of treatments, and the method of preparation. [ABSTRACT FROM AUTHOR]

Highlights • Marine D. hansenii and S. rhizophila inhibited F. proliferatum by diverse mechanism. • Mycelium growth and germination of fungus were inhibited by marine antagonists. • D. hansenii + S. rhizophila increases the efficacy-biocontrol of muskmelon rot. Abstract Separately and in combination a marine yeast Debaryomyces hansenii and a marine bacterium Stenotrophomonas rhizophila were evaluated for their biocontrol potential against Fusarium proliferatum on muskmelon fruit. The results show that the mixture of yeast and bacterium in vitro reduced the growth of F. proliferatum, possibly due to either by direct parasitism, nutrient competition, lytic enzymes, biosurfactants and/or volatile organic compounds (VOCs). Disease incidence and lesion diameter caused by F. proliferatum on muskmelon was reduced significantly, especially when fruit was inoculated with the mixture of D. hansenii + S. rhizophila. These results indicated that D. hansenii , S. rhizophila and their combination treatments were effective for the postharvest biocontrol of fruit rot on muskmelon. [ABSTRACT FROM AUTHOR]