## 3 Discussion
Indeed, 2-phenylethanol--previously observed as the primary volatile produced by other yeasts, such as _Saccharomyces cerevisiae_--has been shown to control pathogen _Sclerotinia scleroorum_ in vitro and bean seeds, to have a lethal effect against _A. flavus_ and to inhibit the production of aflatoxin in sublethal doses. Furthermore, high concentrations of 2-phenylethanol can cause alterations in the biosynthesis of amino acids and proteins in the mitochondria and the nuclei of fungi and bacteria [17; 45; 54; 55]. Additionally, 2-phenylethanol isolated from _K. apiculuta_ showed inhibitory activity against green and blue mold in citrus fruits caused by _P. digitatum_ and _P. italicum_[19]. It was also shown to play a critical role in the antagonistic activity of _A. pullulans_ against postharvest fruit pathogens both in vitro and in vivo [56; 57]. Next, PUCV-VBL biocontrol VOCs 1-butanol-2-methyl, 1-butanol-3-methyl, 1-propanol-2-methyl, and phenylethyl alcohol have been previously reported in other fungi, such as _M. albus_[58], _Trichoderma atrovide_[59], _P. expansum_[27], _Gloomerella cingulata_[60]; and yeasts, such as _S. cerevisiae_[61], _S. pararosetus_[62], _C. intermedia_[38] and _A. pullulans_[51]. Although various combinations of BCAs and or chemicals have been extensively investigated [63], there has to date been no description of bacteria _Glucobacter cerinus_ and yeast _Hansenispora osmophila_ reported together, or their effects against bunch rot diseases affecting table grapes. Thus the VOC inhibition activity in this study adds to the results from previous research into BCAs. For example, our study is supported by past results on _Hansenispora warrant_, which was shown to be an effective BCA in, e.g., controlling fungal rot in strawberries by biofomigation using VOCs [64]. It reduces the natural development of decay in grapes and strawberries and maintains quality parameters [28; 57; 65; 66]. It also exerts biocontrol against chili fruit rot [67] and green mold of postharvest oranges [68]; and inhibits the growth of _B. cinerea_ with multiple modes of action, including competition for nutrients and space, host defense induction, morphology change and secondary metabolites [57; 65; 66; 69; 70]. Indeed, [PERSON] et al., [71] identified different VOCs produced by _Hansenispora_ yeasts during red wine vinifications such as 3-methyl-1-butanol, ethyl acetate, phenylethyl alcohol, butanoic acid, and ethyl ester, similar to results from this study. Furthermore, the findings in this study are further supported by the literature on alternative fungicides. [PERSON] et al. [72; 73] found that volatile compounds of _Streptomyces globisporus_ JK-1 inhibited spore germination and mycelial growth of _B. cinerea_ and _P. italicum_ in tomato and _Citrus microcarpa_, respectively. [PERSON] et al., [42] and [PERSON] et al., [74] indicated that VOCs of _Bacillus_ spp. were antagonistic to _B. cinerea_, _C. gloosporoides_, _P. digitatum_, _P. italicum_, and _P. crusto_. Similar inhibitory effect on conidia germination by VOCs produced by two _Aurebsidium pullulans_ yeast strains L1 and L8 with 2-methyl-1-butanol, 3-methyl-1-butanol, 2-phenethyl alcohol, and 2-methyl-1-propanol against five postharvest fruit pathogens in vitro and in vivo [51; 56; 75; 76; 77]. Notably, the antipathogenic action was shown to be highest for the combinatory PUCV-VBL biocontrol. This finding is similar to [PERSON] et al., [78], who attempted to reproduce the spectrum of naturally occurring VOCs of _Creatocystis fimbrata_ in proportions calculated using GC-MS analysis. The pure chemicals or several combinations (butyl, ethyl acetate, and ethanol) did not show any inhibitory effect. According to the authors, inhibition likely remains due to synergistic effects among all _C. fimbrata_ VOCs, including molecules not detected using current identification methods. Indeed, VOCs have been known to rely on synergistic effects against phytopathogens [58].